Ashe is really a subpar AD Carry, and is really only useful for her never ending slow and her Ult.
regarding all the argument surrounding ashe: I got into a similar argument on facebook recently and this was basically the summarizing post:
"ashe is probably one of the best late-game carries just because of her slow which enables her to kite almost any melee DPS and chase effectively (especially once she gets phantom dancer). however, her lack of a steroid and a repositioning advice can be incredibly painful for her laning phase making her unable to lane effectively against the current popular laners such as graves, sivir, trist, etc.
in addition, the change to cleanse has made flash+cleanse much more popular on AD carries, basically nullifying any threat a random ashe arrow will have throughout the game. combine that with the hugely increasing popularity of QSS on AD carries and you have a carry that's still strong but just outdated."
Define what you call "better". How do you define that something is better than something different ? How do you define that having Vayne's true damage is better than having Ashe permaslow ? You could say some champions are better than other if their kit was exactly the same but with different numbers, which is not the case.
The reason some champions are picked more often is because they fit in the metagame better (Who needs Ashe when the support carry wards and CV and the tank has an AoE CC ?), people like them (Zilean is way more used in US teams than EU teams), or because they can caught unprepared noobs from soloqueue easily (Shaco, Rammus,...).
I don't talk about Soloqueue because as you said, everyone here is retarded. If you watch some pro streams, you will realize that FeedShotGG (yeah, that guy who does like 0/5/2 90% of his games right now) did 11/0/5 every game with AP Shaco when he climbed the ladder.
LoCicero carry his team every game with Pantheon mid at Top ELO,...
In soloqueue, it's not about OP or UP, it's about "noobstomping" abilities. If you watch Doublelift, one of the best mechanical players in the game, he still got stomped by mid Pantheon because he wasn't paying attention and overextended. ELO doesn't matter, people still get fed or feed at top ELO, so what happens here isn't relevant.
And Tier List's are bullshit because they're based on popularity more than strenght, if you look at Elementz Solo Tier list, Twitch is fucking rank 5. Twitch is like the king of noobstomping in Solo queue, with Shaco, and this isn't the only one.
"Better" can be defined by tournament play and how a champion holds up in lane. Arguably, it's hard to make a judgment call on whether Caitlyn is better than Vayne, but we can make certain hypotheses like "Kog'Maw typically loses to Caitlyn in lane" or "Sivir can only really be countered by Vayne or a good Graves player". From this we can build a generalization and say that "Sivir and Tristana are flavor of the month champions who are very powerful right now
in the current metagame". Similarly, Ashe may be a great champion, but she's having a difficult time surviving in this Cleanse-heavy, Graves-popular meta.
Solo queue is definitely about noobstomping ability, but I wouldn't say that tier lists are bullshit. They're an accurate representation of what is and isn't popular in the current meta, which is generally an accurate representation of what's stronger than everything else currently. For example, Rammus is considered very strong right now in solo queue, but that may change in a few weeks if people learn to play around him. He'll drop on the tier list, but that doesn't mean that he became any better or worse, just that he's not as viable. Tier lists are about viability, not the inherent quality of the champion.
play cass. i always had the same problems with being passive and last hitting as an AP, but cass makes both of those easier. i would really suggest playing some games with her whenever she's free, if you're anything like me you will end up being better with her than any of the others there
Always learn to last hit with autoattacks since you WILL run out of mana quickly early game if you keep last-hitting with abilities. In addition, you'll be pushing the lane. Once you get blue buff or a Tear, or if you're simply playing a push-heavy champion (morgana, cass, karthus), then you can start spamming abilities.
i usually just rush bloodthirster now on GP since i always am packing smite when i jungle him.instead of going cloth 5 potions i just get elixer 6 potions. sorta a high risk high reward playstyle but its been working out.
Elixir 6 pots is a waste, IMO. Most champions can get along fine starting cloth, regrowth, vamp scepter, boots, or doran's blade. Elixir is essentially a waste of 250 gold early game and you shouldn't be buying it unless you absolutely need it to jungle (which is highly unlikely in the new jungle).