Bad luck with mewtwo...
Answers
This is the problem with legendaries in general being too easy to get. People are spoiled, and have no perspective on what is a good pokemon. How would a 96% Mewtwo have any more value in practice than your 84% one?
For the record, my three Mewtwos are 67%, 71%, and 80%. And they do their jobs just fine (well, the 71% is new, so he hasn't been powered up much, and is on the back burner for now).
An 80% legendary is a great pokemon. If you raid a ton, and especially if you spend money, you will get better ones than that, which is great, but there's really no such thing as a bad legendary. If my only Kyogre was my 67% one (yes, I have two worst-possible legendaries, and I'm a free player), I would power it up, and it would still be far and away my best water type. My best Zapdos is 80%, my best Lugia before his recent revival was 80%, and my only Moltres is 82%. Am I complaining? No, because they are good pokemon. I also have a 98% TS/WC Raikou, and a 98% DT/O Rayquaza, so RNG goes both ways.
The problem is that the easier it is to get ridiculously high IV's, the less the entitled masses appreciate them. They should have made legendary IV's range from 0-100% intead of from 67-100%.
#exraidsforalllegendaries
I took a 2209 to 30. Then I took a 2216 to 30. Then a 2227 to 30. I got 3 more still at 20. Then I got a 15a/11/15, it is stalled at 37 bc out of rare candy. EX-raids are very inconvenient (for non-college students), reason I've skipped the last two invites (I'd take the 12 Mewtwo candy those likely would have given me but work/out of town).
OP, Just wait until the next one if you aren't thrilled with this one
Bad luck? You got 3? I consider myself very lucky to have 2, despite 75% and 82% IV's.... got my first at lvl 39. But I know many players at my current lvl 40 never got an EX raid pass, so I would never complain.
And I'm happily investing rare candy in my 82% one.... may never get another, and I'm fine with it.