You are so right. I had a hard time with my PB as well until SOs, but I guess thats the case with all ATs you're not used to. Heck, my pb is sitting around lvl 39 at the moment and I have a great time playing him. I dont go the whole all human route or even tri form. I run a simple nova/dwarf setup when i can tank or blast and just enjoy all the class has to offer. It gets to be a ton of fun just customizing the character to what I enjoy doing as opposed to a min/max perfect build. PB is great for that since you have several different options on how you want to play it. Im glad you stuck with it. Kheldians are tons of fun.
** Human melee powers have higher dmg than dwarf ** So I opt for Tri-Form because then you can use all the class has to offer 
But yes you can play them MANY different ways!
I have a ton of fun on my Khelds and I also wish for people to push through and test out all the khelds have to offer be it a PB or WS. End is an issue and stamina isn't too hot on khelds IMO ( depends on your space ) but thats what conserve power and stygian cirle is for 
Issue 24 PPM Calculator // The Great Makeover: The Vindicators
I have no doubt there are players like myself who have deleted several Kheldians before ever reaching level 20; they are just so frustrating to play early on! Ive never surpassed level 15 before and I keep going back to my scrappers.
Well, I was determined to reach level 30 before I pushed the almighty delete button yet again. Ive heard it said a couple times that Kheldians are much better once stamina is taken at 20. Last week I reached level 20 and took stamina. I then reached level 22 and loaded up on level 25 SOs. What a difference! No, Im not nearly as strong as my scrappers at the same level, but Im having a great time with my new PB and more importantly Im not frustrated!.
I cant say if PBs will become my favorite class. It might, but its too early to tell. All I know is right now Im having fun because I enjoy the change of pace this guy provides; I feel more like a superhero than I did on my scrappers.
Anyways, I just wanted to share my experience because Im sure there are others out there like myself. If the above fits you just give it some more time.