Bienes,
Wholesalers are just one of many different resources that can be used to find a good deal. There are wholesalers who understand how to analyse a real estate opportunity while others have no clue. A truely dedicated real estate investor should look at as many deals as possible in their targeted areas. The more wholesalers you network with, the more properties you are able to see.
To say that wholesalers only have bad deals is unfair. Anybody in the game is capable of pitching a bad deal wether it be a wholesaler, realtor, fsbo, investor, rehabber, bank, ect... It is entirely up to the investor to make the final analysis and decide if its a good deal. Set a criteria and apply the formula to as many opportunities as possible. Wholesalers are a great source to find those opportunities. You were correct in assuming that many wholesalers only sell to newbie's due to the lack of knowledge on the investors end and lack of good deals on the wholesalers end.
In order to take full advantage of a wholesaler and minimize the bs, i suggest you lay down the specifics on what you want (location, price, purpose, size, ect.). They will start looking specifically for you based on your criteria and contact you as soon as they come across a deal that would work for you. As time goes by you will learn which wholesalers are worth staying in touch with. You definetly want to be on that stable list of buyers you mentioned if you are dealing with a wholesaler that is any good.
Wholesalers are like free employees... if their numbers work... why wouldn't you use em'?!
Sean