The problem I think that actually arises in the DH/RT/DW cross over is not what skills the characters get and have access to but for what cost they get them.
200 xp to a space marine is for the most part usless, it will probably get you a rarely used basic skill, 200 to a DH acolyte is wonderful as you can generally get two very good skills (except clerics who typically pay 200 for there good skills as they get access to a wider variety of them). A space marine needs to recieve about 500 xp per session to keep him progressing steadily, unfortunately if you give a DH caharcter 500 xp they advance miles in one go.
I personally think this problem is more noticable in DH/RT games where everyone is human (being a marine has a hell of a lot of perks), a starting RT character begins with a similar number of skills and talents as a starting DH one albeit a different skillset (their xp level is higher not their actual capacity), if you give a RT character their recomended 500xp per session they level at the same rate as a DH receiving 200xp per session. A DH character with the same amount of xp as a RT one will always have more skills and talents as his counterpart (and will likely be topping the table on attributes as well), this is particularly noticable where the combat talents are concerned (compare a guardsman with 5000xp to an Arch-Militant with 5000xp).