The current mod 8 design of action points sees many many many tier 4 actionpoints never purchased because of the incredibly high cost with relatively little gain (except in specific circumstances... like HP, dmg and a few others)
This is becaues you get most of the benefit for 1 action point, then a little bit more benefit at the cost of 2 more action points but the benefit is less then or equal to the benefit you got from that first action point. It's really quite bad to have decreasing returns on increasing prices... it's just really sucky sometimes... and means you can't really focus in on those abilities, because it would jsut cost you WAY too much of all your other abilities.
I know there's some fixes for some of these types of enhancements, specifically for the paladins and the ones involving the turning attempts and things like that. Paladins are a very enhancement heavy class and I know that it's designed in a way that they don't want it to be possible for everyone to have all the enhancements as well as their race based ones...making us choose different paths instead of having everything(or only having a little bit of everything..). Getting back to the point... the pally turning action point costs are being touched so that to get the top tiers you 're not spending ridiculous amounts of action points for relatively little gain, and mostly with the intention of just opening up a class prestige line.
I was wondering if any of the other expensive lines would be going in this direction, especially in the skills area (usually huge wastes of action points, what's the point of having all these tier 4 skill ranks when anyone who invests in them, will generally be really really messing up the build from being able to afford many of the more useful APs(except for a few VERY rare and specific, non game breaking if made cheaper, circomstances).
Where I'm going with all of this is: skill and other class based enhancement lines need to be made much cheaper instead of the 1,, 2, 3 , 4 path.
The biggest and most obvious one to me is fighter Kensai. Fighter kensai is nice and all, but spending 20 action points just to get to kensai 3 (10 each for fighter attack boost 4 and critical accuracy 4, both things that because I'm in the kensai line, I wouldn't want on my character because the kensai is essentially covering me fine on those lines with all the other pre reqs and benefits, that they because nice little extras that I'll be having on but I honestly wish I could spend those 20 action points in other places... ) The other problem is that with Kensai 3 costing a total of 8 APs for the tier 3 prestige line + another 3 for the 3 weapon specialties, +2 more for the capstone, that leaves me with only 3 action points next mod to spend on something else... I'm not complaining about that, but I am very sad that it's costing me so much to get kensai, I'm honestly starting to believe it's not worth that many action points and I'm seeing more and more the appeal of the builds focusing only on kensai 2, ranger6, and 2 monk levels.
Anyhoo, sorry for the long run on sentences ... I'm tired and suck at writing clearly...