First off, I'm okay with the balancing for summoners. There's not much variety going on in the arena already and we really need a change of pace, as summoners are usually needed to counteract summoner teams as well. I'm eager to see new valiant changes as well that could shift the arena meta considerably if done well.
So... While I do agree that summoners are stagnating the meta too much, I'm kind of disappointed that the concerns on archer trigger teams haven't been addressed before this.
Archer trigger teams exemplify what "overpowered" is all about - it's an RNG-filled monstrosity where your most precious damage dealers can get wiped out in the very first turn, because they really love to target the lowest def targets in your team. What's worse is that archer trigger team effectiveness is heavily dependent on equipment, unlike summoners. Just try to survive a heavily geared archer trigger team's onslaught. It doesn't really matter what your team composition is, they'll all die eventually because of nearly unlimited aura triggers.
Sure, you can get lucky at times and avoid dying on the first turn, and eventually sweep the enemy to victory, but the fact that it's almost a 50-50 (or far higher chance depending on the enemy's stats and crit rate) of winning every single time isn't very fun. Even archer vs archer teams tend to just be which team gets to attack first, or which team manages to land the first critical. Again, it boils down to one-sided fights depending on who's the luckier/better geared team.
Summoners are neat because it does make you think a little bit - you decide where to summon it, and which to focus on (most likely the enemy summoner as well) to gain a huge advantage. At the same time you're pretty much in under constant threat of losing by making a wrong move, but the pressure makes it fun. Above all, stats don't matter as heavily, and only when the disparity between gears is really huge (like the enemy has a full 6 star prestige equipment for all of his/her heroes) it becomes a one sided match. I can speak for experience, and I'm sure some others shifting around the top 100 rankings feel the same as well.
At least with summoners, the events lend you one for free by the end of each event so everyone has a chance to compose their own summoner arena team, giving nearly everyone a chance to compete against other.
So, any thoughts? I'm sure I might get flak for actually defending summoners, but I think we can all agree that the archer meta prior to this was just absolutely awful compared to what we have right now.