So, I finished my last ever playthrough of Fallout 3 on Xbox. Liberty Prime is blown up only for the Brotherhood to revive him again in Fallout 4, because why get rid of a popular character? When you assault Adams AFB the game literally gives you a superweapon that makes the ensuing fight much easier, though it is admittedly very fun to use. The best part of the DLC is probably the medic armor you find in the Olney sewers, because as hbomberguy said in his long video about Fallout 3, it's a nice piece of worldbuilding. The new enemies have weapons that ignore ALL armor which is stupid and frustrating, but I guess that incentivizes the player to use their most powerful weapons to obliterate them ASAP instead of hoarding the ammo for those guns forever, so there's at least a silver lining. Overall, I'd give it a 5 out of 10.
One extra note about Point Lookout is that while you learn about Calvert (brilliant professor from a family not at all like the Kennedys who has gone insane), you don't learn anything about Desmond apart from the fact that he's British and he survived the Great War...somehow. At least, that's all I learned in my last playthrough. I'd probably give this DLC a 6/10, partly out of sympathy for being the best overall DLC, even if the hillbillies stupidly have diamond-tough skin.
I guess I might as well rate the other ones too:
Operation Anchorage: 5/10. It's fun enough, and there's a hint of meta worldbuilding in how the simulation is constructed...but it's basically a Call of Duty clone in the 2008 Gamebryo engine, lol.
The Pitt: 5.5/10. Not sure how Pittsburgh survived the Great War, but the morally grey central conflict is a change of pace from the rest of the game.
Mothership Zeta: 4/10. It's...a complete non-sequitur based off an easter egg, with all of the potentially interesting elements simply not expanded on at all. The weapons are super OP though and can kill Deathclaws in like two shots, which is fun.
Uh...Fallout 3 as a whole, 4.5/10. It could have been a lot better as an RPG and as a Fallout game, but it's not the worst game out there. Fallout 4 had better shooting and environmental design but it made the writing and RPG elements even worse.