True...All spins are generated randomly
True...Games are "based" on a percentage payout based on the symbols,lines etc.
False...Game payouts are totally based on these symbols and lines etc. having a fixed percentage based on random generation of combinations.
Take for instance Immortal Romance or Thunderstruck if the II if the Wild Desire or Wild Storm are also random then imagine the nightmare for the game developer, a totally random event giving a random number of wilds could generate all sorts of random percentages for the game that might take forever for the casino to claw back.
My Theory...The spins and wild features are produced randomly and placed in a packet of say 5000 spins to be sent out to players.
Next the software calculates the payout on those spins and compares it with the percentage required to make the game profitable over a reasonable period of time.
If the packet contains too many big random events they simply discard that packet and generate another one.
Simple all spins are random,it's just whether they choose to send you that spin or another random one generated later.
That's how I would do it anyway.
You can still win big or lose big but in the end you never see the casino going broke because they had a bad run of big payouts that week or month,it never will or can happen.
I have to say that you seem a little confused. Your opening True, True, False statement means you are contradicting yourself!
Re the Wild Storm/Desire features; I don't think these are a "nightmare" for the developers at all, and there is no more reason for them to be non-random than another other part of the game.
You think the number of wilds given can not be random - I will try to explain why it can be:
Just suppose, that instead of a RNG & computer program deciding how many wilds you get, it was done using raffle tickets.
There are 10,000 tickets in a big bucket; 1 of the tickets will give you 5 wilds, 9 of the tickets will give you 4 wilds, 990 tickets win 3 wilds, 4,000 tickets give 2 wilds, and the rest (5,000) give you just 1 wild.
You close your eyes, stick your hand into the bucket and pull out a ticket which reveals your number of wilds. Is that a random event?
That's what the casino's computer does - except electronically of course!
The casino could still suffer a string of "Jackpot hits" - but if they are not sufficiently funded to cope with this they shouldn't be offering the games to start with. There have actually been many cases of casinos closing down because the players won too much.
I'm RNG holds true. Remember, reels don't spin randomly, the 'page' of reels, of the payout is random. The win is determined from the point of hitting spin so the landing reels (the result of all 5 reels) is already pre-determined from the moment you hit the spin button. What is random, is when YOU hit spin. What is NOT random is the result of your spin. That fifth reel may spin slower suggesting oo, oo, it might be that 5th symbol I need, but that 5th symbol is already decided from the moment youve hit the spin button.
Errr... that doesn't make it non-random...

If I'm missing your point - please explain!
KK