I agree with firehawk and say you should probably wait till the big update (4.0 wasn't it? I forgot). Sorry if my explanation is long beforehand.
First, because they alternate events between Muse and Aqours now so songs used in the events aren't as boring. I think the reason why songs aren't as varied between events is because they need to have "easy" and "hard" songs in the pools, and the easier songs are very limited (Pure Girls Project and Moshimo Kara Kitto for pure as an example) which is why they appear very frequently.
Second, school idol skills being implemented, which is exactly (quoting yourself) "something else to grind for (maybe items we could equip it our idols to improve their stats?)." Though it is still RNG, I think it adds a different dimension to the game, for example choosing between using seals to get blue tickets or re-idolizing an SR to increase the skill slots of the card.
Third, idolization using seals is another way to add "goals" to the game. Since the quality of the event cards' art seems to be lowered (or maybe it's just me not liking it, dunno) I've been tiering events simply to gain silver seals to idolize my URs, knowing I most probably won't use the SRs for my team since they aren't strong enough anyways. This is just me as an example, could be different for you though.
tl;dr: imo you should wait for the next big update in EN since it addresses some issues with the game you're mentioning. Here's the full update log for JP if you haven't read it yet:
http://love-live.wikia.com/wiki/Love_Live!_School_idol_festival_(JP)_Updates, scroll down to the June 22 and 29 updates. Hopefully it clears things up for you a bit!