It was a good balance of easy and hard. You die much more than in past Mario games, but you also get many more 1-Ups. If you want Games Over, avoid 1-Ups. As for laziness involving Luigi, none of the things that weren't changed affect the gameplay. You want laziness in controlling another character that makes things suck, look at Yoshi in Sunshine.
ShadowBrain, how long will you exaggerate any con that you can and become blind to how insurmountable the pros are in comparison? Or just get things completely wrong... what's with the idea that Mario sidescrollers were hard? Super Mario Bros. and World are WORLDS easier than SMG. At least, to a seasoned SMW player. Dare I say SMW was less fun...? It has reigned as my favorite game ever since I first played Nintendo. Nah, I won't go that far.
Besides, hardness and fun are not directly related. That's why amusement park rides don't have difficult controls. A challenge is good for a game, yes, and Galaxy offers plenty of challenging stars and galaxies (Luigi's Purple Coins = Satan). The hardest thing I can think of for SMW is... getting to Soda Lake.
Lastly, end the whining, PLEASE. If you so badly want to go back to the '90s, turn on your SNES. Is it me or has everything you've said against SMG been countered with facts? I'm just beginning to think you've never actually played Galaxy at all.