1. Although Guilty Gear is a long running franchise, I have admittedly never played an entry in the series. So, of course, I wouldn't buy it due to an enamoration with past iterations. As a 2D fighting game fan, however, I am slightly interested in playing it. I don't play too many fighting games (I really only play Smash Bros), but I'd like to play a few of the popular fighting game series to see what I've been missing.
2. In my experience, fighting games are never really all that easy to get into, in the sense that a "seasoned veteran" of a fighting game usually finds every miniscule exploit in a game's engine in order to win, which could be pretty alienating to new players. In this case, I don't really know how favorable the experience is toward newcomers, since, well, you know, I haven't ever played it. >_> But I do know that its presentation shows obvious anime influence, which could be unappealing to those 2D fighting fans who are accustomed to slightly more western designs, like in Street Fighter.
3. Well, again, I can't fully answer this question. Though I have surmised through watching videos that its gameplay is much more akin to "traditional 2D fighters like Street Fighter than button combo heavy 3D fighters like Mortal Kombat, or party fighters like Super Smash Bros Melee, I don't have a very extensive knowledge of Guilty Gear's gameplay mechanics, or the gameplay mechanics of most 2D fighters for that matter.