I will admit to being somewhat disappointed to see shield potions being defended in such a manner. It doesn't look like ego, the responses are reasoned and well considered. To be honest it would be easier if it was ego because that wouldn't suggest that I've misunderstood part of the core design philosophy behind ED.I read Sandro defending the mechanic, and I fear the game is going in the wrong direction.
Combat since these things arrive has taken a very noticeable nosedive IME, rendering PvP battles where shield potions are a factor (which is nearly all of them I hasten to add) tedious and infuriating in equal measure. Previously combat between unmatched foes was usually swift and decisive, as it should be; when equally matched combatants engaged the battle was lengthy and a real test of wits, as it should be. Now we face proportionately lengthy battles between unmatched foes, and battles that quite often have no end between equally skilled combatants; worse, add a 'big ship' into the mix and you face battles of such length that the most likely result is simply someone getting so bored that they'd rather jump out.
Increasing the cost of shield potions is a good start but I see it having almost zero impact upon their negative influence on the PvP game. (Not to mention how their use in PvE is all but 'God Mode Engaged' for the player.) Shield potions are at their most egregious when mounted on big ships, and no amount of cost increase (short of extreme) is going to stop the commander of a big ship from piling them on.
If combat duration is a concern, then boost the durability of some of the ships. Don't shoehorn in restoratives from every other MMO game out there; they work in MMOs, they don't work in a game that fancies itself as a gritty space sim(-ish).
If giving the underdog a greater chance at survival is a concern, don't add something that simultaneously drags more evenly matched PvP battles into the realm of abject tedium.
I also note that some amount of acceptance has been displayed in calling these things what they are: healing potions. Gone is the old spin on terminology that attempted to position SCBs as being something else. That, to me, at least, is a good sign because it indicates that the problem is beginning to be recognised.
TL;DR: Elite Dangerous needs a far more elegant solution than SCBs. That's not to attack the concept of a timed, shield-based temporary assist; it's an attack on the crude and damaging implementation of that idea.