Well to me, I have a hard time playing blues with a humbucker. I'll take a single coil any day. Is your Ibanez 24 frets? If so, this squeazes the pickups into a tighter configuration. If a guitar has the same scale and only 22 frets, the neck pickup is further away from the bridge, giving it a greater tonal discinction from the bridge pickup.
Also, a guitar with a longer scale means that the same strings are strung tighter, giving more "spank" or "snap" to the tone. Most Ibanez have a 25.5" scale, with is about as long as they come before you start getting into extended-scale guitars, so you're probably at a good spot there.
Now, I'm a huge SRV fan and that may not be the type of blues you are talking about...but there's a reason that the Strat is such a widley used guitar in blues...long scale + a good single coil pickup = blues guitar, for me anyways.
Make sure it's properly setup. If you're not sure how to go about this, take it to a luthier (note: not Guitar Center). They will, among other things, make sure there's proper forward bow and action height for how you play. Sometimes this is all that's needed. If the neck feels good to you, and the frets aren't worn, it might just take some pickup work.
Find out of a coil-splitter can be added if you don't have one. It would be a fairly simply mod, and if you switch to a push-pull pot, it won't even change the guitar's appearance.
If you can still find a Mexi-Strat with good fretwork, they are decent finds. Especially when you consider the aftermarket for super-easy-to-swap pickups. There are SO many pickups out there if the stock ones don't suit...but before you swap 'em out, just try adjusting their height. You'd be suprised the difference it can make.
However, humbuckers have their place (B.B. King, anyone?).
Blues, perhaps more than just about any other type of guitar-music, is a very personal experience. For me, it's a overdriven tube amp on its clean channel with tight strings and a good single coil on a ash-bodied bolt-on. For someone else, it's a hollow-bodied set-neck with humbuckers on a 24 3/4" scale neck and an amp that won't break up until it hits "11."
I'm a rock dude, primarily, so I've got a 25" set-neck with double humbuckers.