I find the time limit to be irritating and detracting from my enjoyment of the game. Rather than impose a time limit on the effectiveness of a potion, I would prefer if the potion worked for only one 'application.'
In other words:
Let's say I want to improve a sword by enchanting it. Rather than scrolling thru the available enchantments while on the enchanter's table, then backing out, imbibing the Fortify Enchanting potion, and then doing the work, I'd like to be able to simply drink the potion, get on the Enchanter's table, and then leisurely scroll thru the menu to decide how I want to enchant the weapon. The next item I want to enchant, I'd just imbibe another potion.
Anyone see things differently on this?