I wouldn't mind seeing a special vendor that will sell you some no drop trade skill combines based on recipes you've already mastered, like an apprentice. Cost per item would cost more than acquiring it by hand, but that is the price you would pay to have someone else do it. This would help ease the tediousness of all trade skills and encourage more to pick up trades in an ever shrinking market.
That's the thing, what you suggest would be accomplished by adding the recipe book basically, which the client already supports but was purposely removed and the manual and tedious way was kept.
Let that sink in, they had to actually code out a function that would bypass the manual combining and allow the player to just click combine and auto-inventory....
Also doesn't address the requirement of the only class to have to pay to do their main function, or juggling inventory and bank space dedicated to all the types of arrows.