Im not sure what problems you could be alluding too. The X45 I have works just like the X36 (only its hats work...X36 worn out after 2 years of my abuse).
There have been some VERY slipshot reviews of the X45 -vs- the X36, several have made statements that are just not true. More than one has lamented about the new pinkie trigger, failing to realize that the updated hook part comes right off leaving you with the identical control of the older stick. There are also some who dislike the new "feel" of the stick. The new stick does have a completely new feel, and yes it is a bit distracting as first, but you get used to it after a few flights, and it is much smoother and overall much easier to use. I also much prefer the new safe cover being more in line with the rest of the universe and have the cover over the button, not the cover IS the button (who thought that one up)
The only big negative I have found is the stupid light up buttons. Its a stupid gimmick that add ZERO to the stick when you use it (I dont have light sensative fingers....do you?) and I find is actually a distraction when Im watching a DVD or something in the dark.