Going the Knight Enchanter route may have just made me lazy about investigating some of this other stuff.
And after 66 hours I am finished. The final mission was trivial I have to admit. Finished every side quest but not all of the companion quests. Oddly Cole was crossed out for the final mission, not sure if a personal quest kicked off before that wouldn't let me take him with me but a bit annoyed I couldn't back out to find out without reloading. Had to use Blackwall in his place for the final.
I didn't care for Cole much but his final mission kind of seemed important since it involved another NPC that probably disappeared on you at the end. Blackwall didn't make it to my end game.
Blackwall ended up being my love interest. I finished his quest line off, found out the truth about him! I got 75% of the trophies and the ones for finishing on hard and nightmare are silver and gold so worth a good few % each so didn't do too badly for one play through. Odd that I didn't get the one for 'recruit a powerful ally to help defeat the dragon' as it is just in the normal quest line , perhaps a bug like me not getting the one for the 10 dragons first time .
It's not really over powered in my experience, but it does have aspects that can allow you to win battles purely by using the Knight Enchanter skills. For example, I used a single KE skill + a very basic mage skill to defeat the demon Imshael in Emprise.