As a long time developer I just sit back and smile. I've too many years experience with users...
See there's where we differ. I have had only 2 users. Yes, two. Maybe I hold some fucked up view of this, but this is my hobby. I write addons because I want to. I see things in the game that are broken or seem stupid and I want to fix them. I want to make my UI better. Out of some general kindness, or maybe it's a sign of respect to the other devs that have helped me, I share my code with ya'all. I listen to ideas and complaints, try to implement those I like, and tell the others that their ideas suck. I've always been blunt and honest, you don't like that then leave.
And this is me being blunt: If you don't give me money, you are not one of my users. You do not hold any sort of special privileges in my world. That doesn't mean I won't listen to what you say and give honest consideration to it... it just means I don't have to be nice to you so that you keep coming back to buy my shitty wares.
Besides, who in their right mind would pay for software? Writing code is simple. It's fixing people who are too broken to use your software where the money (and hassle) is.
*edit* Indie subscribes to this same belief, the only problem is noone uses his addons *ducks*
Try out a lot of different addons that will satify your needs if you can't write or modify your own. Ace2 addons are not necessarly better performers than non Ace2 addons. I have reverted back to many non-Ace addons, simply because the Ace2 addon performed poorly and was not worth saving the memory. Other times the performance and memory use is superlative to some addon I was using. This is one of many places where I go looking for new UI ideas and tools, as well as educating me on how to create or alter addons.
A lot of people around here enjoy Ludwig/Ludwig SellValue, because the author (Tuller) is highly respected for clean and efficient coding. There is also a pre-populated list for SellValue you can download in the comments section of the mod on WoW Interface. ColaLight and MonetaryValue are Ace2 mods that does this as well, but lack any data initially.
I can't think of any Ace2 replacement currently designed for this.
Sorry, don't think there is any. You'll have to look for a small, standalone mod for this.
Don't think there is any for this either. Ludwig is a exceptional alternative to lootlink/itemsync/etc for storing item information but for purely expanding inspect information, I still use smurfy's edition of SuperInspect.
Sorry, I'm not familiar with this. I know there's some various tradeskill mods floating around like cgCrafty, Manufact, TradeskillInfo, Fubar_tcgTradeskills, but you'll have to check em out on your own.