Plenty of potential, would have to be done correctly though in my opinion. This would mean dedication to the coding and the time it will take, as DVS already said he can't at the moment, maybe this can be something to focus on for an update. Even adding something as unique as this at a later part of the server, it'd still be massive.
The main issue, it could cause major unbalance. If it was me I'd have it so the added stats/new items, gave a percentage chance of an increased hit on X spell, as opposed to (example: 30% increase in tdb). For instance, say a 13% (random number plucked out of thin air, but you get the gist) chance of a x2 hit with TDB or FS etc. It still makes the item worth having, without making it particularly OP.
E.g. Magic Shield may decrease damage taken by 50%, chance being 8%. Again random numbers, but not overpowered, and although number seems low, it could still be critical to survival. Obviously should this be implemented as this scenario suggests, the numbers will have to be worked out by the team, but I'd think this would be a smarter way to go, to limit and major imbalances it may cause.