In my opinion, those kind of subjective impressions are not meaningful. If the units being compared volume matches, with no EQ engaged etc., to make sure we are just comparing the sound quality of the amplifiers, then I am 90% certain (based on objective facts and data) that you won't be able to tell a difference. If EQ is involved, then it is a significant variable that may allow you to tell the difference between the Onkyo, Yamaha and Marantz.
If you are interested in 7.1.4 Atmos, you can do it with the SR7012, but not the RX-A2070. They also have very different Room EQ system but if you don't use them then it is a moot point. I know Audyssey XT32 Sub EQ HT (Marantz) works very well in smoothing the low frequencies in my rooms where one or more subwoofers has to work well together with my bass capable L,C,R speakers, but I am not sure if Yamaha's YPAO is as good.
I don't know about the 2070, but I know Marantz and Denon's mid range models do run quite warm, but it only costs $10 to put a quiet fan on top. It is not really necessary if you have say 6 inches of clearance on top for air to move, but an external fan should help extending life.
The talks about one is better for music are really just talks, or hearsay. In a properly done AB comparison, as I mentioned earlier, I highly doubt you can tell a difference. However, there is no point debating such a topic as it is obviously up to you to choose what to believe.
If money is not the issue, it seems to me your only good reason to swap it for the SR7012 would be to do 7.1.4, and/or you prefer Audyssey to YPAO. According to our resident insider
@M Code, Yamaha AVRs do have better reliability records.