Comparisons to AC13 are just crazy. If they had the 3 day notice Steam release, but released preview videos, screenshots, had multiple gaming websites play it early, etc. - few would be complaining about them not providing information pre-release. A lack of relevant info for making the purchasing decision is very different to having a lack of release information.
Yes they should have a date in the UK - but they aren't in the realm of AC13 in any respect.
The only thing I don't get is why the steelbooks are a pre-order bonus when the UK release hasn't been targeted around building up pre-orders. I'd have just sold it as a special edition.