What about repairs? I am not that rich. I spent almoust all my money on stupid things,even if i didn't do that i still be unable to use some hevy armor every round.
as i said, IF is not useless. is almost useless with anything lower than 45-50 armor (my default gear now, that's why i have only 2 IF on my actual build) but is really helpful when you wear heavy gear and plan to charge the mess taking account teamwounds, arrows, multiple attacks. my best siege build was 24/15 with maxed IF at 31. was really forgiving and with said 72 armor, i could take a lot of teamwounds, a lot of weak 1h swings, and 5 serious 2h/pole cut blows. for the mathematic sake, at the same skill level, sustaining 5 hits with the need to land 1 or 2 to kill (what a 41p morningstar with 8PS could do) will put you in advantage. especially in tight siege zones.
and even 5ATH with duel gear (black lamellar, studded leather coat, leather boots, nordic helmet) gives you enough (just enough, not a lot) mobility to counter 18/24 hiltslashers. you even have enough wpf to feel comfortable with a MW high tier greatsword (SoW, danish, german) while being a 3hit machine with longsword.
now i'm 21/19 and i'm bit disappointed as i'm an aggressive facehug kind of. often risking wounds to land chamberblocks, now i simply can't as i go down with 3 and often 2 good hits. before even with a black lamellar i was able to sustain 3 full 2h/pole hits.
it's a matter of taste and fighting style. a 21/21 will sure do better in battle in my opinion... but for siege, no.