So far, the only fleets with a prayer below 1k points are Chaos, Necrons and eldar. Orks, Tau, and IN are largely up a creek. Nids I'm not too sure of, no one plays them round here, and I'm too broke at the moment to buy another fleet to playtest it myself.
Nids would have a hard time shooting it to death, but they have other means. Feeder tendrils murder high armored ships.... especially ones that like to be close like the BB. Tau would probably be more ok than you think, they do have a fair amount of lances at 1000, probably around ten.
IN having a hard time? Heh. You haven't seen the all gothic fleet people like to play (for god knows what reason), and the most common ship taken 'lunar' has half lances, so they would be fine at this points value unless they did something strange.
Eldar however... probably wouldn't do so well, as bombardment cannons are better than lances against eldar. Also the sms can keep up with them. Although, they are quite lance-equipped.
Orks... well having played orks for most of a decade, and most of my games against space marines, is the reason that I don't like the idea of a 4th shield on a BB, it's already hard enough for orks to take out as is. (as their normal method for dealing with high armor, boarding, isn't effective against the smurfs)
But I do understand the reasons behind it, primarily the fact that 6+armor closing < 5+ armor abeam. It's something that hurts the orks as well, as their ships appear to be tougher on the outside, but IN and Chaos will turn abeam as soon as possible and be more defended. Not to mention that it's much easier to get internal damage on a low-shielded target.
Look at a retribution, if it is closing, it will be tougher than a BB (due to additional shields), if it is abeam, it will be much tougher than a BB, and it's weapons are effective from a distance, so it doesn't have to sit there and get pounded from 15cm. This was the way Admiral D Art (I think, might've been sigoroth) explained it to me.