Warning: The following statement has no quantitative substance. It is completely conjecture based on hearsay and opinions of others!
It is my understanding that some things are just not to be.
1. The 220 (without considerable cylinder modification..which is to say porting) will never have the top end of the 200.
2. The 200 (without considerable cylinder modification..which is to say porting) will never have the bottom end of the 220.
I think it's easier to make a 220 more like a 200 than it is to make a 200 more like a 220. The former would tend toward metal removal in the porting process, the latter would require some metal/substance addition.
It doesn't have to be impossible. Decide which direction you're leaning toward, and chose from there.
If you want bottom end and lots of it...and don't ever plan on missing the topend of things, get a 220.
If you want a bike that HAS a topend (were not talking about an mx/125 like topend you realize) and can be modified to do probably anything you'll likely want to on the bottom, get a 200.
Here's an added bit of effluvia. My riding buddy had a kdx200 (he's orange now). He's started bike riding (dirt) when he was something like 6 yrs old. He's good. He's ridden a lot of bikes, knows what they are supposed to do. He rode a 220 (had to get the rider out of a jam..the rider couldn't get the 220 up a particular hill). He wasn't all that impressed with it.
That 220 was in stock trim. His comparison was to our somewhat modified 200s.
Were not talking about comparing a 426yzf to a cr125. It's not THAT big a deal.
Good luck. You'll likely get a big kick out of either one of 'em!