I'm going to have to disagree with you on that Neonivek. It is a strategy game, it's just not a strategy that conforms to the standards set by other games. You have to use and abuse core game mechanics to have a chance of surviving a battle(Item World/Land of Carnage most of all). People say it's all grinding, but the grinding itself requires thought, preparation and strategy. There's also a myriad of levels in every game that can't be won unless you solve geography puzzles. Even if the solutions are relatively simple at times, I would dare to say it's considerably more strategy required than anything in FF Tactics, Tactics Ogre, Front Mission etc.
I am not saying it is all grinding (since you have to exploit to get around grinding) but once you are in a battle all strategy gets thrown to the wall and forgotten
What you are describing is a puzzle game at best.
Also here is a reason why I can argue against its strategy:
When a exploit is found in Disgaea that breaks the game... it is part of the game (strategy is a meaningless component afterall)
When a exploit is found in ANY OTHER game that breaks the game... it is a negative aspect of the game. (For example the gamebreaker character in Final Fantast Tactics)
It isn't so much that there IS no strategy (but I would argue that) it is that it is meaningless and is considered an unimportant aspect. You want to just go fight the last boss with no thought? Go ahead you will succeed! Want to fight the final secret boss with no thought? Well you will lose UNLESS you know the exploit!
So I guess I could just say... Disgaea isn't a "Serious strategy". Also by the by the Relm of Chaos is a puzzle section and the Item World is also mostly a puzzle section. Though even if Disgaea was the GREATEST strategy game ever known it STILL isn't the same style of strategy. The goal is to break the game rather then playing within the game's set rules.