Capital Wasteland has
Brotherhood Of Steel
Enclave (Now that's an unholy alliance)
The Outcasts
Enclave's Orbiting Satellite
Super Mutants including Overlord and Behemoth
Deathclaws
Feral Ghouls including Reavers
Raiders Armed with Assault Rifles, Combat Shotguns and Missile Launchers
Liberty Prime
The Lone Wanderer
More easier access to Fat Man's and Mini Nukes
Albino Radscorpions
Talon Company
Mojave Wasteland has
NCR Soldiers, Veteran Rangers, and Rangers
Caesar's Legion including Legate Lanius
Mr. House and his securitrons
Deathclaws All forms
Feral Ghouls including Reavers
Brotherhood Of Steel
Raiders including Jackal, Viper, and the Fiends
The Great Khans
The Boomers armed with Cannons
Super Mutants
Cazadors
The Courier
Who wins well I'd have to say the Capital Wasteland. The reason being
The Orbiting Enclave Satellite would decimate the Mojave Wasteland army, The Super Mutants are higher in numbers with the CW army including the Behemoths, The CW BOS and Enclave have better armor then the MW group does. CW has the Liberty Prime and the Enclave Orbitial Satellite would destroy the Boomers Cannons. The MW has more people but they aren't as well trained as the BOS or the Enclave. The Lone Wanderer vs The Courier would end in a draw. The Securitrons can be destroyed with Pulse Grenades which the CW group has more of. The CW's Fat Mans would decimate the MW's army so yes the CW would win but it wouldn't be completely easy.