This was a bad experience for me overall. Some people will have a different opinion, and I respect that, this is just my feedback.
1 - Having Ranked Rewards on a mode that does not get balanced OR updated, is the same as having ranked rewards in ARAM. It's actually worse, since ARAM gets updated from time to time and it's fun.. but wtv.
2 - Instead of 3 bans (6 total), there should be 6 bans (12 total), the unbalanced nature of the mode creates much more downright OP champs than in 5v5.
3 - Portals are almost useless since the last change that was years ago.
4 - 3v3 for me, it's getting a Dominion status, if it wasn't for the ranked rewards, I would probably not play it, and even so, I almost gave up due to it being extremelly boring game. Sometimes I go jungle, and it's... dull. Sometimes I died because I had nothing to do, and wanted some action instead of being in a brush waiting for camps to spawn, so, I invaded enemy jungle, or made a dumb gank, and got caught.
5 - Do Vilemawn ASAP, it's GG.
6 - Sometimes you get ahead, and still need to play 20 min to finish the game, even if enemy team has no way to return to the fight due to team comp.
7 - 3v3 needs a real, massive overall. I enjoyed 3v3 before the changes, when we still had a drake (shyvanna would love this) and a red buff, now... it's just team setup and win. Portals were fine but... ridiculous now.
8 - Unbalanced skill matchup. I play against plats and sometimes diamonds constantly, while I was silver. Every game has a mix of silver / plat / gold / diamond (sometimes). No one plays 3v3 because it's bad, and the people that play for the rewards are not even having fun. (I asked the ppl who played with me).
This is trash game mode.
This can be the easiest or hardest league to climb, depending on the champs you play and get a nice comp. We really need more bans for next season if Riot still wants to give ranked rewards in 3v3.