The weapon swap functionality use to be terribly laggy on PC. They did a lot of improvements to streamline things, and I personally haven't noticed problems in that area for a loooong time (others may have different experiences, of course).

I can't speak to how weapon swap performs on consoles, but I imagine that if it is a widespread problem the developers will work on improving it, just as they did on PC/Mac. Just might take some time to work out the kinks.

If this is only happening in PvP, it might just be part of the general lag that still plagues Cyrodiil. PvP lag has been a problem for ages. There are some fixes going in with the next Major Patch that are supposed to reduce some demands on the server and improve lag, but I doubt it will make things perfect.

I agree. Its really laggy and I find it annoying when im switching to my buff/shield bar for my sorc. I have horrible internet connection. My GF has really fast internet and when im over there I can switch bars seemingly fast. So it may just be a problem with your internet. Just a guess.

The weapon swap has been horrible since the game launched on PC. They eventually, after several patches, improved it to semi-working level, but broke again with the weapon swap lock feature. If you perform some action, the lock will activate and for a short period of time commands to swap weapons/bars are discarded, therefore one has to fit into windows in between locks to successfully swap weapons (or use potions, that is blocked too); stop doing anything, swap, start doing things again. Prior to this, weapons swapped during action (it cancelled skill animations).
Which is remarkable, because while other problems were, say, glitches, this seems to be deliberate. And even though I can imagine they had some reasons, how they could go on with it is beyond me. I mean...come on, the game discards player input now. How is it supposed to be even remotely responsive? The first person playing it after this change must have noticed how crippling and infinitely worse it is. Is the code really such bloody mess that hiding it behind the lock was the lesser evil? Or nobody actually plays the game anymore?
And I am not even talking about speed (or lack of it) when weapons do swap.

So, it is so bad on PCs it can hardly be even worse on consoles.