I think the new style is brilliant, actually. Clear, and does what it says on the tin. It tells you that you are at a railway station and gives you the information needed.
To most people now, and even more so in the future, nobody cares a fig whether they are at a "First Group", station, a "Stagecoach South Western" one, an "Arriva Train Northern", or "Northern Rail (Capita)", or "Northern Rail (DRO)", etc.
We wouldn't change the signs on the M6 in Birmingham to a different colour every time the principal maintenance contractor changed, and then have a different colour scheme when you run into Staffordshire and South Cheshire (and another one for Lancashire / Cumbria / Greater Manchester).
It does the job. It tell the TOCs that no, they can't pour money down the drain every four years on the latest trendy colour scheme, and it gives the signal "this is the national rail network", just like road signs say "this is the national road network".
Mixed case is more readable I believe - research from the early 1960s suggested that people look at the shape of the word first before decoding individual glyphs, and all upper case words have the same shape as each other. Hence the use of mixed case on roadsigns. (You spot the difference straight away if you ever drive in Ireland, where the English language words are in a heavy uppercase font and the signs are cluttered and harder to read).
As for Scotland and Wales, whilst their devolved government TOCs can, and will do, something different (which they were doing anyway before the Review came out, but even if they weren't the "we have to be distinctive from the English" lobby would make sure of), Network Rail will surely follow the national guidelines. Therefore trackside signs, and major stations, will be in Rail Alphabet 2 I'd have thought.