easy solution: make greatswords/top tier 2h/poles require more STR.
I'm already salty that it takes till level 12-15 to pick up a battle axe. A 3/3 build is still a grown ass man, and any peasant could pick up an axe to defend his home. For the sake of game balance, I think its appropriate where weapons are now though. I would never suggest letting people play 12 str Flamberge and Great Long Bardiche builds, but its bogus enough that you can't pick up your favorite weapon for 10+ levels even when pumping full strength with point conversions - even some mid-tier ones like a persian battle axe, or a support weapon like the english bill. I miss the ol' 15/24 english billd.
Could pull a dick move and make the greatswords 16/17 str - a non-multiple of 3, but still over 15.
Honestly though - as far as agi vs. strength goes, it depends on how far they stray from balance.
18/18, great. Some would argue too slow to warrant being so weak. No real edge, aside from being able to utilize skill points.
18/21 - lethal speed, just enough damage
21/18 - lethal damage, just enough speed
This is where straying from balance makes the strength argument meritYou can stack as high as 27/12 and still be able to utilize impressive footwork, more than enough to warrant sacrificing the athletics. You can deal lethal damage to ANY character, light or heavy.
When you invert that to 12/27, you still have an extremely lethal build. Here and beyond lie the cons that start to outweight the pros with agility.
Survivability is the major deciding factor. Everyone focuses on damage - the ability to affect the world around them, because that's how we are as people. Take into account getting killed in 1-2 shots from ranged, 1-2 swings from melee, a couple horse bumps, even (and especially) teamwounds. STR also affects your maneuverability in heavier armors. It
allows you to make more mistakes. We're flawed, we lapse focus at times, we get outnumbered at times, we miscalculate and even get fucked over at times.
K:D doesn't mean much, but if its anything to go by, my KDs for my 27/12 english bill gens were significantly higher than my 18/21 gens. Personally I prefer my 18/21 build, but I was certainly in my prime in heavy armor, 27/12, backed by a squad of incredible teamplayers. High strength is just as much a teamplay build as an agility is, because being more grounded, you should really take responsibility and be in the frontline. Gutting guys, avoiding hits, blocking pikes, watching your flanks and covering those of others in massive melee engagements, pretty much demands that you perform well. If you're a 12/27, you'd die from the first mistake made, and nobody would judge you for it because they wouldn't know any better themselves. With focus and commitment, strength grants you lethality and survivability across the board. Agility only allows you better control of choosing your battles. You only need as much as the situation demands. Strength has a much more passive benefit, and I think that's what bothers people.
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I'm currently 15/21 shortened military scythe cav and was one-shotting people in chain mail by 12 strength. On foot I wear heavy ass pronoia, and still catch most archers running away, or at least match their speed. 12/27 studded warclub, or shield are fun builds. 27/12 was my best performance. 18/21 was my first infantry build ever, and is still my favorite. Its all about positioning on the battlefield, and agility does not and SHOULD not dictate that, but rather your mind should. Think about the bigger picture and consider weapon types, damage types, and versatility.