The gameplay is far from being revolutionary, actually it's quite limited (there is no real leveling system, fighting encounters are scripted and not random).
Well, you're saying it's not revolutionary because it didn't have the typical leveling systems and random battles that most RPGs did at the time. That sounds a little contradictory to me. Scripting the battle locations was perfect for Anearth because it wants you to focus on the puzzle and exploration elements. Most other RPGs at that time had much simpler dungeons to wade through: go right, left, up, down, find chest, unlock door, fight boss. Random battles comprised the busy work to do while you stumbled around. Anearth had gargantuan dungeons with a very wide variety of puzzles and loads of secrets; it actually had fun, challenging things for you to do inside its mazes, so it didn't need busy-work random battles.
And when battles did take place, I found I was able to use far more strategy than in most, if not all, other 16-bit RPGs where I'd usually just hammer the attack button. Enemy formation, enemy location at any given moment, enemy capabilities, my own party's strengths and formation, different assault methods to utilize--all of this would come into play in virtually every battle. (The expected counter would be that your experience with its battles involved far less strategy than what I'm claiming they involve, but I know for a fact that people have been stumped by its fights before, and the solution isn't the typical "level up more" approach that gives you an easy out in many of Anearth's peers.] And the game definitely has a legitimate leveling system: the pacing is so perfect that if you fight intelligently your characters will be right where they need to be stats-wise at every point in the adventure. I prefer that to running around in circles leveling up like you do in many old RPGs. (And if you are the sort who likes to level up in the traditional repetitive style, there ARE battles that you can repeat in certain places.]
It's definitely not as good as, say, Kaze no Densetsu 2.
I love Xanadu 2, but I'd cite it as being far more limited than Anearth. It's very straightforward and simple; you bumble around while enjoying the magnificent beauty of the whole experience, and in a mere few hours it's all over. The caliber of puzzles and labyrinths that Anearth boasts are nowhere to be found. They're two different types of RPGs and we're beginning to compare apples and oranges, but it seems odd to present short, simple Xanadu 2 as an alternative when criticizing Anearth for limited gameplay. If anything, you might've cited Xanadu 1 instead. THAT game is epic in scope and has a monstrous final tower that presents many intricate challenges.