When they impliment systems, they can select which they want actions based on, Real or Displayed skill. There is no more difficulty in one than the other.
They Chose to make stable slots based on your displayed skill, so it isn't an exploit.
(besides, the most you will get from it is 2 slot and you have to be relatively close to having them for it to work)
My own tamer gets +2tame/+3lore from his ring, getting those last 2 slots, leaving 5 for meditation.
So if he just finished tame and lore and put on a +5 meditation ring for the same results, would that be an exploit?
IMO +skill items work fine, but they just made too danged many for some skills. Necromancy and Stealing are the best examples. You can have GM in either for less than 40 real points due to items.
They should have simply restricted each skill to 1 worn item beyond jewlery.
And talimans should be limited to +5s.
As to the pending nerf to sampires. I hope they are simply planning to change the requirement on casting Vamp.
The spell isn't all that powerful by itself. It has penalties for the bonus and IMo they are nicely matched.
The problem is simply that people are able to use it without the requisite skill - all due to the overabundance of skill+ items.