Celebrim
Legend
DM response to so many qualifiers: All Storm Giants are now exactly as strong as you are.
Funny, but as a DM, my general rule is that a wish is granted using the minimum amount of magic to complete the request. Any wish that can't be granted by the amount of magic available to the sort of being granting the wish, typically a powerful mortal spellcaster or a minor demigod, would automatically fail in a perverse way.
The outcome: "All Storm Giants are now exactly as strong as your are." requires vastly more magic than making a single mortal as strong as a storm giant.
The typical manner in which a request like that would be fulfilled by me is the player would receive a Girdle of Storm Giant strength. This requires the least amount of magic. I would in general not be happy with this sort of request unless it was being made to a full god of some sort, as its generally above the ability of a wish to create such a mighty item on its own. So rather than creating the item, the typical result would be that the wish would facilitate stealing the item, and now the PC is the enemy of whomever used to own the item.
The slightly perverse version is to note that "a giant" is fulfilled if there is at least one storm giant as strong as the character. So the character would now be as strong as that one venerable, crippled storm giant, who is now unable to even lift himself from his bed. This version gets really perverse if I set that giant's strength at 0. "OK, you wish to be as strong as a giant, you are now as strong as Clangbang the Venerable." Saying you wish to be as strong as a giant is more arrogant and less precise than simply saying you wish to be stronger, which for me would probably get the response, "Ok, you are now stronger.", unless the wish granting party just hated the PC.