Ok so to bring this thread back on topic I'll explain why I'm not a fan of our infantry.
First of all, let's assume a competitive setting. Like, people bring the cheeselists. If they don't, well then pretty much anything can become viable. Likewise, a comp system will naturally shake things up.
I'm going with 2400 points because that's what I know best. I only ever play bigger games when we play some sort of campaign/add-on (like Storm of Magic) so 3k is not something I know too well. At 2400 points, the lists you can expect to face are roughly as follows:
BM - Weak
BR - Multiple lances. HKB Lord. Double Treb. Double L4, dobbel scroll. Possibly triple Peg knights. Multiple paladins.
CD - Gunline with K'daai, Hashut/Death and Chalice. Khan's for chaff. Possibly Iron Daemon and Wolf Riders.
DoC - Tzeentch heroes + core, Nurgle special + khorne rare. Furies. Literally over a dozen drops. Possibly hounds. Possibly Epidemius with Nurgle core and possibly Kairos.
DE - Shooty avoidance or full flying circus. Possibly SCs.
DW - Gyrospam: 7 gyros, 3 cannons, lots of BS shooting. It simply is -the- go-to Dwarf list. The alternative is double cannon, double organ gun, double block (longbeards + hammerers) but it's inflexible compare to the gyro-list.
EMP - 1+ spam. Magic: Life/Light/Heavens. A variation on the 1+ spam is all-skirmish core with strong counter-pushers and Light coven.
HE - Teclis Light Coven or monster mash. Possibly cavstars as well, if the meta isn't Life-heavy.
LZ - Skink cloud deluxe. Combined with either air cav, razordons or temple guard. Possibly Tetto'ekko
OK - Gutstar, poisoned Maneaters, double skillblaster. L4 Heavens.
OnG - Gunline. Trolls, either 2x9 or 1x9 and lots of impact hits stuff (chariots, manglers etc). Savage orc bunker.
SK - Double WLC or double HPA. Tons of Slaves, strong magic. Gutter Runners.
TK - Sphinxspam or Necrospam + Light Coven or Death.
VC - Screamspam + death. One of the worst lists to face in Warhammer, it's just that terrible.
WoC - Herohammer! Lots of super-strong characters backed up by chariots, for the most part.
WE - L4 high + L4 Shadow with lots of waywatchers and poisoned/trueflight and Wild Riders for counter-charging and waystalkers for character sniping or full-fast cav with Light Coven.
Ok so now we have an idea about what the meta looks like. Let's go back to our concept here, running WL + SM.
First of all, the assumption that SM is a hammer unit is not correct. Taking a look at the list above, they can pretty much beat nothing in combat apart from non-combat units and possibly a few more. By and large however, they lose badly to the vast majority of units out there. The same goes for Lions, but they are stubborn so they'll stick around, besides you can congaline them or dual-line them to reduce damage income and simply hold an enemy. Assuming you run L4 Death you can even keep purple sunning your pinned enemy!
Secondly, SM and WL largely fulfil the same duty: Volume of medium-strength attacks. I say medium because with the insane amount of high-t and/or super-save things out there, you really need S7 to be considered high-strength. S5 is the new S4 etc. Thus, they can be compared directly. WL are simply better, which again boils down to stubborn. If SM were stubborn, I'd be willing to at least consider them.
Thirdly, let's take a look at how such a High Elf list would look like. Basically you have 900 points invested in 2 combat units. At 2400, that leaves 900 points for characters and rare selection after the mandatory core has been spent. How would you go about spending these? You could go all-out push and take two frosthearts, a helmbus and minimum characters. You could go magic heavy with dual L4s and RBTs for a defensive build. You could do a mix with both RBTs and a Frostheart and a single L4 for a combined arms approach. The problem with all of the above is that the list struggles to do much. It's not fast enough to push well (it could -possibly- be done with dual Frosthearts), it's not strong enough to defend well and your points are spent in an awkward manner which doesn't benefit the list. A hybrid could be done, but such a list, even if played well, will likely lose a lot of games because it can't push and it cannot hold (I played a lot of games with a similar list only with PG + WL instead of SM + WL). Again though, in almost all of these cases you'd likely be better off with 2x WL.
Lastly, let's take a look at the other builds in the meta. Notice a pattern? Combat infantry units are near extinct. With a few noteworthy exceptions (DoC Plaguebearers for example), people just don't take them. Considering some of the awesome choices out there on paper (CORE Nurgle Chaos Warriors with GWs for example), it's logical to assume that the meta has simply evolved past this. Basically, things are either fast, resilient, shoot/magics well or supports, or all of the above (in the case of Warlocks for example). You can "tactics" all you want but when your enemy puts a unit of Harpies in front of your M5 unit in T4 after you spent the first 3 turns foot-slogging across the table, there is nothing you can do to have your crucial charge hit home: It simply won't.
So let's revisit a few of the exceptions in the meta: DoC Plaguebearers and Teclis WL coven.
DoC Plaguebearers typically work in a context where there are multiple other pushing units, such as Beasts of Nurgle and Plague Drones. What's interesting to note is that they are extremely resilient and hard to shift, kind of like White Lions (largely because of stubborn in the case of the latter as they can reduce damage input by congalining and have the BOTWD protecting them). The Teclis WL coven list features White Lions to protect that all-important cargo, one of the most hated special characters in warhammer. BOTWD + stubborn is what does the job here and enough of the Lions will deter enemies from closing in because high volumes of S6 threatens nearly everything (that said, this build does have a few very hard counters where enemies can just run in regardless of S6 spam - WoC 1+/3++ lords with stubborn crown and third eye for example).
In taking a second unit though the BOTWD protection disappears and with SM, you are not stubborn either.
To conclude, the problem is that our infantry units simply aren't strong enough in the current meta to make an impact. Infantry combat units in general aren't worth taking and ours are not the strongest, nor are they core tax points. Previously we had PG + WL as a popular combo, which largely boiled down to Shadow support (with the durability of PG, Shadow is an excellent lore) and shooting units (archer + reaver core and RBTs + sisters in rare).
If you do wish to go down this route regardless, I would suggest trying out a push build based around simply having too many wounds for most enemies to chew through:
Archmage, Level 4, Lore of Death, Dispel Scroll, 245
Lothern Sea Helm, BSB, +1LD, 140
17 Silver Helms: FCG, Shields, 421
2x 5 Reavers, champs, 2x 90
28 White Lions, FCG, BOTWD, 444
28 Swordmasters of Hoeth, FCG, Razor Standard, 439
2x 1 Frostheart Phoenix, 2x 240
Great Eagle, 50
Army Total: 2399
As always, the question is: Is this the best way to spend your points? In this particular case, you could spend the ~440-490 (assuming the Eagle isn't mandatory) on more characters and/or support, for example. Death was chosen here to benefit from the Lions' traits and to add some actual punch to the list. Purple Sun and the various snipe spells are great counters to this list's weaknesses (or a lot of them, at least) and Soulblight + D&D are great for boosting you in combat, doubly so when you have this volume of bodies and high static res across the board.
Generally with this build I'd deploy Silver Helms near the table edge with Swordmasters on their other flank. Lions go 3 wide with both characters next to them and the flyers whereever needed. Something like this:
Silver Helms (5 wide) - Swordmasters (7 wide) - White Lions (3 wide). The Helms on one flank and WL on the other allows you to slowly push forwards without the enemy being able to isolate the Swordmasters. The WL are stubborn and have Naval Discipline so they're not going anywhere and the Helms are protected by the table edge. With 2 Frosthearts as well, you should have the needed flexibility to keep going and counter most threats.