What's the appeal of DragonQuest, if I already have five plus editions of D&D to meet my general fantasy needs? And why 2nd edition, in particular?
I never played the 1st edition, and am not an expert on the subject, but my understanding is that it was little more than an arena-based combat system.
TSR published a 3rd edition after taking over SPI, which was almost identical to the 2nd edition, but made certain mechanical changes that revealed their poor understanding of the rules they were altering, and stripped out everything that might be deemed "controversial" (this being when many outsiders thought we gamers were all a bunch of secret Satanists) -- the College of Black Magics, demon summoning, etc. It did, however, incorporate some material that SPI had intended to publish in a later supplement to the 2nd edition (the College of Shaping Magics, for example), so it wasn't completely devoid of value.
While DQ and D&D are both fantasy role-playing games, they "feel" quite different in play. Combat is deadlier (and much more tactical than pre-3rd edition D&D), but still great fun. Magic is less predictable, much more dangerous (to the caster, at least), and organized by Colleges that result in practitioners who resemble classic literary "wizards" much more than in D&D.
On the downside, while the rules are for the most part quite balanced and extremely well thought-out, there are a few gaping holes (the Skills section being a particularly weak area). And of course, there's no official (and precious little unofficial) support for the system anymore. I haven't played it since 1999.
But it still holds a special place in my heart.