Riot has announced the rebalancing of runes and with this, a very significant change to Lifesteal Quints, taking each one down to 1.5 percent each from 2 percent. Armor runes are also being reduced, but they are giving every champion a 4 flat armor bonus to compensate. This is mainly to give an alternative to Armor Seals, which have been the defacto Seal for a long time now. Health Seals are looking to be an emergent favorite, going from 5.35 to 8 health per rune. The gold value of each Health Seal is slightly better, considering the 4 flat armor buff every champion will have, and also deals with mixed damage on a rune slot that previously was meant only for physical damage reduction. And this rune got buffed on top of all of that.

With that said, I expect Armor Penetration Marks to become popular again in Season 4 on a lot of physical damage dealers. In the past they have been a favorite and do really well when paired with Flat AD Quints. With the potential of lower early and mid game armor values, some will even opt for both Armor Penetration Marks AND Quints. With the combination of the feast changes (up to 3 from 2 hp per last hit) and the Lifesteal Quints nerf, it may be a good idea to have 2 pages for AD Carry/Marksman this season. I expect some top laners and junglers to use these pages more often as well. The most popular page for Season 4 AD Carries will probably be:

9x Health Seals, 9x Flat AD Marks, 1x Flat AD Quint and 2x Lifesteal Quints + your choice of glyphs

However, the page I am most excited to run is a mixed page:

3x Health Seals, 6x Armor Seals, 3x Flat AD Quints, 5x Armor Penetration Marks, 4x Flat AD Marks, 3x Flat MR Glyphs and 6x Scaling MR Glyphs.

The beauty behind the mixed page is that you look like you are running a standard flat ad and lifesteal rune setup, but you actually have 6.6 Armor Penetration hidden in your build. You should get the best of both worlds in effective hp and damage with this combination (at least in my opinion). Some people are saying Health Seals will unequivocably be better on AD Carries (which is true up to 1000 hp), but in actualityArmor Seals scale harder into mid and late game when dealing with physical damage. Only tanks get MR per level, but everyone gains HP per level and Armor per level, which is one of the reasons why I run MR per level and flat armor. Since all champions start with 30 BASE MR, running 3x Flat MR Glyphs and 6x Scaling MR Glyphs will be highly favorable for mid to late game focused summoners and I can see myself running this set of Glyphs on any page.

In my opinion, flat hp on AD Carries is kind of like fake resistance to me. It doesn't scale into late game, as we stated. At 1000 hp, Armor Seals are better than Flat Health Seals. If someone buys a Blade of the Ruined King against you and you have Health Seals, you now die much faster than you would if you had Armor Seals (or a mix). Anyone running an ad/armor penetration page will deal lots of damage to a Health Seals Start. This counts for junglers, ad carries and top laners. Plus with percentage health in the game, I don't think I would want to run 9x Health Seals on my AD Carry page anyway, although the resistance to multiple types of damage make them much more attractive. Perhaps I will have to set up 3 pages this year.

Conclusion

I highly recommend having 2 or 3 pages set up for AD Carries/Marksmen in Season 4. The nerf to Lifesteal Quints likely isn't enough to stop early game champions from picking them up. Since this page is geared towards early game laning and securing the right to farm, it potentially outvalues any potential resistance you could have had by going a different runeset. You can always buy flat resistances anyway, and you probably will want to.

If you decide you want to run a strong laner with even more aggressive runes, the armor penetration page may be for you. This is very good for lvl 2 all-in lanes and also if you have a sustain support and want to pack a bigger punch. Regardless of what you choose, there are more options available to you now. What you can achieve is limited only by what you are willing to give up.