I inherited a Tormek 2000 and it has a SG-250 wheel that is about 190 in size currently.
The wheel is not level across the top ( basically has a valley in the middle of the wheel. Should I replace the wheel at this point or what?
Yes, and if you do not have a Truing Tool, you should get one - of the new models.
I also was given a SuperGrind 2000 some years ago. The expense on these machines is quite high. Luckily, they are really easily updated. True up with the TT-50 jig and do what I did and replace the guide, shaft, water tray ect. I used sharpensupplies.com for parts. Or, just dive in and start sharpening and see if it is your thing. I must warn you it is addicting. I am a newbie too and I'm searching the house for things to sharpen. 8)