Ty all. Good tips. I figured the following:
1) I was being a bit lazy and not micro managing battles. Time to get off my ass and take care of those nasty beserkers and lions.
2) I tend to use a lot of veccavi sentinels, PABs, Ravenstern wardens at this stage of the game (no castle/town yet). VSs and PABs are not that useful for field battles, only really useful as cheap garrisons. This is especially so when you're facing some lord with tons of lions. Changed strategy to using lethaldrin's weekly noldors in place of VSs and PABs. Also trying to get some KO troops by bounty questing and shattering the target. That should get me enough good quality troops (I find that armies based on lvld recruits simply aren't strong enough to take on armies including KOs). If I fail to get KO troops (Sometimes they don't give troops even if you exceed target by 15-20 times), I'll try save some blackheart squire prisoners and lvl them up to knights, and I love rogue knights too.
Are there any other tough tanky troops that people enjoy using early game? Pls not hero adventurers - I prefer not to use them
3) I was taking castles close to enemy centres. I'm guessing that AI chooses which castles to seige based on a) troop numbers, b) proximity to centres, c) how recently taken it was, d) recent defeats by their realm and victories by you. I'm going to change this and take something not too close to centre and race around whittling their field armies down before cap and after cap. Hopefully I'll run into some nice prisoner stacks and get some garrison troops that way.
4) 10+4 surgery eh? I've normally survived on lower, but you're right I guess - the more the merrier, especially since I'm already taking too heavy losses.
5) Noted re castle garrisons. I've just come from Perisno and they have a really nice feature where garrisons get immediately sorted by lvl, which automatically ensures that your best spawn first. I forgot for a second that this is not default... thanks for the reminder guys
6) I can solo alone to 30, but I do enjoy lvling my companions

I'll stick to lvling my companions, its more fun for me.
7) I hate losing sieges purely due to KOs and CKOs set up there.
Anyone know a good tank unit to hold walls that can be easily and cheaply gotten? Pendor Bladesman perhaps?
Also how are people finding the new pilgrim line, particularly war priests and battle brothers? Battle Brothers should in theory be super troops (not bad WPs, ok weaps) but I find they do barely anything. WPs I like though... squishy but lethal if timed right and placed right (ideally a surprise flank attack from over a hill safe from archer fire).

I need to start disrupting enemy attacks. Again, I got lazy after the past few games with end-game troops (household guards in perisno and CKO on the last pendor playthrough). I forgot just how powerful those troops are in comparison to normal troops. If I keep letting the enemy armies do their thing, they'll keep steamrolling me. Back to basics
Ty all.