What you describe is what makes me love Kheldians. The fact it's not trivialy easy for everyone.
Not all things in the game need to be made for and enjoyed by everyone. I personaly hate Brutes and SoA's for the opposite reason you have problems with Kheldians, their simply built to be trivial to play well.
I enjoy having to make choices and in some cases sacrifices to make my WS play well.
I simply do not "get" the percieved slot crunch people seem to find on Triformed builds. The first thing I tell people when they ask about slotting advice on WS's or Khelds in general is to dismiss the notion that powers need to be 5 or 6 slotted to be "good".
People who primarily play the "regular" AT's have simply become spoiled by having plenty of slots to "at least" 5 slot every power they have in their primary and secondary and dont feel any power is done until that point.
With IO's, and sets specificly, it is nearly trivialy easy to get what you need out of a power in 4 slots or less, and most of the time it is possible to have all relivant powers (non-duplicated) in a Triform build slotted as well (under 8% difference in all aspects) as a fully 6 slotted Human form build.
Is it easy? No.
Is it for everyone? No.
But it is fun for the segment of the population who enjoys tinkering and learning something difficult to pull off.