Surprisingly, it took 'till Tome of Battle for valkyries to get statted up in 3.5. They're the strongest and largest (being Large) of the book's three monsters, and come with a hefty eleven RHD.

Like all outsiders, valkyries have an assortment of random immunities and resistances, as well as +7 natural armor, DR 10/cold iron and SR 17. Land and flight speed are both about average for a Large critter. Their ability scores are excellent, with physical stats ranging from 22 to 27 and mental ones from 13 to 16.

They get both Two-Weapon Fighting and its Improved version as bonus feats, which are reasonably nice to have.

Finally, there's some special qualities. Aligned Strike is not worth mentioning, Electricity Attacks is pretty neat, and between Sonic Burst and Lightning Gaze a valkyrie'll deal pretty good area damage that doesn't take up actions, though the non-friendly nature of the abilities makes them somewhat harder to use.

Last are a number of IL 10 maneuvers that can all be used once per encounter. They range from the good (Pouncing Charge, Prey on the Weak) to the bad (Boulder Roll), and while the usage restriction is annoying it's not like regular swordsages are too great at in-combat recovery. As could be expected, this initiating stacks with swordsage levels, giving valkyries a viable-if-obvious advancement option.

Considering everything, I think +2 LA is fine. It lets valkyries still get 9th-level maneuvers, albeit at a delay, which given their considerable melee prowess should balance things sufficiently. Do discuss!