I don't think you can just call it part of our history and therefore it must stay, on that premise then the whole ground would never have moved on.
I think you have to divide the emotional tie from a practical perspective and draw the conclusion that it would be easy to re-build something that looks the same but incorporates a much larger facility that is more suited to match day revenues. The fact it takes an absolute age to get served in it and then chug down a pint in standing room only where there's just about room to bend your own elbow pretty much answers the question on whether it should be redeveloped or not.
You could recreate it but in a much bigger and more practical form nearby in a "Rover's Return" retro style, whilst providing the much needed beer garden, large screen and expanded bar with food it is crying out for. To label everything old, cramped and shite as historic is to miss the point that this is supposed to be part of the amenities for match day and is just completely inadequate in it's current form and would restrict any future development of the Kop also.
Whilst the redevelopment of the ground is going on for that whole area it presents an ideal opportunity to solve this problem once and for all whilst there is plenty of land available to tackle the issue. The only problem might be who owns it and if they are in favour of the idea.