Good point... Stun Blow and Improved trip are fantastic, but do I have enough feats to even fit all that in if going pure Paladin?
But then I have no CC's which are crucial for soloing in high tier Reapers.
R4 is kind of that comfortable solo level where you can binge watch netflix while strolling through quests.
At R6 it's not much different than R4 except you have to be able to deal with vengeance reapers and you need better self-healing to overcome the penalties (not just cocoon). You have to be a bit more on your toes because of vengeance reapers. Having a bard buffing alt on another acct helps alot with the healing. Some people have tanky healers auto follow them around the dungeon with aura which also works well.
Above R6 I mostly run with 2 guildies and mostly 3-manning R10s. I will run high skulls solo for challenge once and while to test out a build, but I don't think soloing high skulls regularly is something I'd ever be interested in. sometimes I succeed and sometimes I don't, but eventually I'll succeed if it's the right build and I really want to do it.
Soloing high skulls is more about mastering reaper content than build, although generally a tanky build with 80%+ of top tier dps is what works best in high skulls solo. So using ignition with a shield in KOTC with a deep splash in sacred defender is the way to go solo R7+. Bladeforged THF/SWF is great for zooming through R6 fast, but falls off solo above R6. Shoot for a 350+ AC ( you can get 400 easy with past lifes) and 5k hp. High PRR and MRR. You can also make multiple gear sets - one for strolling through R4s and another for high reaper.
For example, you can use a 3-piece vecna tank set and get all artifact the melee power, doublestrike, damage bonuses from other sets - ideally with 2 sets using 3 pieces including a legendary gem of many facets.
As far as a cc, it's good enough cc on a tanky build. Dire charge goes against a fort save and greater color spray is suprisingly effective against low will save enemies even with a lowish dc with just 2 augments and having a high charisma. Just make sure you identify any super dangerous champs asap and take them out. I bluff all the orange and red named reapers before engaging the mobs if I can to make things easier.
Good luck, I would ask yourself the question if soloing high skulls on a regular basis worth it. I think you will find the answer is currently no, although over time it might get easier and of course you might just be more skilled than I am. I still find soloing high skulls challenging and too much work to do for anything but challenge.
All the best on your build!