Arriving en masse they surely are. Karon, from being quite desolate is now pretty crowded at evening times, Mainly Russian from what I can tell.
Back to Patong and I was also around Bangla on the evening of the Brazil v Croatia match. Ate at a beach restaurant and witnessed some well presented, polite Russians eating and drinking a plenty. I had always, in the past, generalised (wrong to generaluse I know but it is what I saw) that they could be somewhat arrogant, and "bulldog bullyish". The latest influx do seem to be of a different ilk.
I sat at Blue Lotus for a while and witnessed a small group of Russians there apparently spending freely again. On checking with the staff, they had bought 48 staff drinks (!), but done in a fun way from what I saw.
Good for business it seems and, of course, good for the staff.
Finalky, as you state, I would also expect to see some Chinese tourists next year.