I can't say whether a wobble is to be expected, but in my experience it was easy enough to fix that I would highly recommend fixing it if you're at all worried.

I had the same issue with my RP1's subplatter so I called the dealer, Music Direct, when it didn't improve after a month of use. I called MD on a Monday and the guy let me know that I did the right thing by reporting the problem rather living with it. He called Rega's US distributor the next day and by Friday my RP1 was wobble-free with a new platter and subplatter shipped directly from the Rega distributor. Replacing the subplatter is as easy as removing the platter, pulling out the subplatter and easing the new one in. All I had to do then was box up the old components and ship them back to the distributor. 

So, my recommendation is if it's bothering you at all just give the dealer a call and see what they say. Much better to check now than to settle with a nagging issue on your $450 investment. 

Hmmm. I wonder whether this is a quality control issue with the entry-level Rega turntables. I took delivery of an RP1 2 days ago, put the platter on the subplatter last night, and the wobble in the subplatter/platter was quite noticeable. Per Rega's included instructions, I left the TT on last night (they recommend a 24-48 hour warm-up period to let the motor assembly settle in). This morning, the wobble seemed somewhat reduced, although it was still present. I'll let it run again for a while and see what happens.  Seems to me I've seen similar complaints on other hifi boards. Has anyone contacted Rega about this?