Heimer feels awful tbh.
Played him in an ARAM and a bot game now, and just from that little bit of time spent playing him I would not ever consider playing him in a normal. Im just going to kind of rant my first impressions, not to really hate on the champ, just kind of pointing out some stuff that seemed kind of lame.
The passive seems kind of weird considering he is a scientisty guy and the animations change a lot. I would really have expected some kind of research or permanent upgrade thing that actually lends to his character. I also think that Heimer should gain the MS when in the range of a turret if anything, because that is honestly what I expected going in. Since it is not though, I have no idea how close to stand next to it.
The turrets deal minuscule damage and ranking up Q only increases their damage by 3. Legitimately, just 3. And they die SO fast, literally to anything that touches them. The ONLY good thing about them is the beam, which yes, it hurts, but the radius in which you have to hit enemy champions is pretty small and lame... and it takes SO SO SO long to charge unless I manage to hit one of 2 kind of hard to hit skillshots.
W is wonky but overall feels OK. Does not really feel that impactful with 5 hits honestly. Can only kill like 2 minions, and barely.
E is hard to hit. It is slow and small and isn't really that impressive compared to Nami bubble. Or at least it doesnt feel like it. Also, the ONLY thing that changes when you rank it up is +40 damage. Like, that isnt really much honestly since that is the ONLY thing he gets.
R is basically a Karma Mantra that feels way less... special. I don't know when to use the empowered Q vs W and the E just seems like the best choice overall. Karma has clear benefits to each Mantra and is the vastly superior choice in terms of which feels better.
I would much prefer a passive that makes heimer seem smart. RQ - longer lasting siege weapon with some range RW - hailstorm of rockets that go all wiggly and home in on different things and leave burn patches RE - less bounce, more stick to someone, stunning and dot shocking TF out of them, then aoe explosion!