Anything is possible. Wait until he's released an update before making blanket statements like that though. 1-90 mpk is obtainable at level 1 through tier III (currently spawnable items), and with that alone, I could continue playing just exactly as I have, when it comes to casting. Further, if MPK becomes worthwhile at high levels, then I may end up with a net benefit from such an update, rather than a loss.
Again, this is part of the reason why a re-working of lifesteal is so interesting. There've been caps put into place on other stats, ESPECIALLY at low levels, that makes the reworking of lifesteal a pure balancing aspect. Truly, things are far more balanced now than ever. Where before, with LPK you could go 1-30 easily enough, then with lifesteal, 30-71, achieving a no-regen (full chain) build, yet could only match that up to 30 on the caster side using MPK and then having to shrine (not a full chain) past 30, now the lifesteal aspect has been balanced out to be about as helpful (perhaps a tad more) as LpA, forcing melee to shrine just like caster.
If MpA, MpK, LpA, and LpK are all reworked, that will be a slice across the board. It won't just hit casters, none will gain an advantage. Further, depending on the exact type of rebalancing done, we may just find that suddenly the restrictions against all of the above, lpa lpk mpa mpk and LS, being used in catas, either removed, or all of them having a chance to take effect in catas, which would be a net benefit to every player in the game.
I can think of about 14,000 possibilities occuring, Ryan, and very few of them are going to have me up in arms the way you seem to think.
Edit: Note that I was using a 16dex 11 luck, 6 lifesteal charm, 191ee lvl50 axe, and a 36 strength 6 lifesteal scale for MQs until this update was released. As I expect I'll be stuck at headhunter until reset anyhow, this update effects me just as much as anyone. And yet again, I'm not overly bothered by it. Perhaps, with all the various caster nerfs I've already put up with, I've simply learned how to adapt better than the rest of you?
With better balance comes better features. Had the attacks not been slowed, we wouldnt have the graphical version. Had the dex not been fixed, we wouldn't have catacombs. Had other stats not been balanced into a spawnable range, we wouldn't have things like Glyphs, and other accessory items. The list goes on and on, and will continue to in the future.
I'm debugging a bug that only seems to (oddly enough) happen to me in my logs. I'm going to try and get that fixed, as I think that may be somewhat the cause of the crash bug that hit us a week ago, then get back to some other updates planned. Hopefully one of these days I'll be ready to implement what was hinted at in the teaser, but still have various things to tweak and balance first.