Ummm...
Being the last few releases, and especially 3.5.3 are more security patches...
Why wouldn't you at least patch it?
I mean... why leave a security hole on your site?
For example, my live site is on 3.5.1, but I've done the patch for 3.5.2 and 3.5.3, and am planning on upgrading it to 3.5.3 very soon.
But to not do at least the patches seems like your kinda opening a door for a hackin ass whoopin