Manamune Stacking Super Slow

In an ideal setting, +4 stacks/mana twice in 8 seconds, is + 4 every 4 seconds, or +1 (stack/mana) every second. Which is 750 seconds or 12.5 minutes.

So in the best case situation, your manamune would upgrade after 12.5 minutes.

Now if manamune isn't your first item, or if you are wandering, or if you are even minion clearing, your manamune is even slower.

Because, for instance, minion waves are timed every 30 seconds. So if I kill my minion wave in 6 seconds .. . no matter how many minions I kill, i get +8 stacks. Then I wait for the next wave (since I likely won't push by myself) and get another + 8 . .. in a minute. Or +16 in 60 seconds . . . as opposed to the ideal +60 in 60 seconds.

I get that maybe few people use manamune and those who do probably get the item first while still in the laning phase; but while its good on some champs, it's not the best first item.

I can say that giving a stack for a minion/creep death may make filling it much quicker; or removing the "twice in 8 seconds"; or even, if the stack rate needs to be controlled, "+4 stacks eight times in eight seconds" may make it better.

But as it is right now. These super slow stacking makes being "FULL" take longer than the game, sometimes.