Even if it seems more powerful at first or second glance... I'm of the opinion you're probably still better off trying it and using it so you actually have a Warlord at your disposal in your game, rather than not using it and waiting hope against hope that WotC gets around to it. After all... in the years it would take for you to finally see a WotC-designed Warlord get published, you and your tables could be running and playtesting the Level Up Marshal and balancing it as needed as you go along. Heck, in truth you'd probably get it balanced for your table's needs way before WotC will actually get around to releasing theirs.
So if having a Warlord is really such a big deal to you and your game... I say don't wait! Take what's available and run with it. (Same holds true for any Psion or Arcane-Half-Caster stans out there.)