With the maximum EV I think there is actually more variance due to the reduced number of bets and lower average wagered amount but I'd have to calculate the average bet size to be sure.
Since you are in both cases "going for broke", the result is either $0 or approximately $10K. Therefore the variance will be LESS with the higher EV, since it also has a higher percentage chance of winning.
------
I understand (and hadn't considered before some of this thought-provoking debate) what you are saying that if you first go-for-broke with roulette you are always (upon success) subjected to the full slots wagering requirements.
However, as you point out, this is also true for slots (upon success), if you get lucky and win the jackpot.
So if you "need" a $10K slots jackpot to survive, then it seems to me you have to decide if it's more likely that you'll hit that $10K playing out your meager bankroll on slots, or going for broke on a lower house edge game like roulette.
Using the previous assumed numbers for slots and my improved roulette method, the chance of hitting that $10K is 1.2% for slots vs 1.46% for roulette. That is a (relatively) HUGE difference.
So... going for $10K roulette win vs $10K slots jackpot... seems like advantage to roulette.
But I think more importantly, roulette allows you to make money on a more consistent basis. There is no way to do this with the slots-only approach.
Again using the previous numbers, a slots-only approach was estimated to have only a
0.2% chance of not busting out!
With the roulette-first approach, you can adjust your chance of a successful cashout by choosing your initial target, something that slots (with a huge fixed jackpot) does not allow you to do.
Lets say you shoot for a $900 target with roulette first, with a 16.2% chance of hitting it. You then play it out on slots, giving you (I'd guess) something like an overall 15% chance of cashing out with a decent chunk of change.
Yes, you have to suffer the full slots wager requirements, lowering your long-term EV somewhat.
But... making a good (positive expected value) bet with a 15% chance of getting
something out, is looking a whole lot better than a somewhat more positive expected value bet with only a 0.2% chance of success.
Sure, I'd take the 0.2% approach if I was convinced (still am not

) it was better... and I could repeat it about 100,000 times.
But since we are talking about bonus hunting, at only 0.2%, you could go a LIFETIME without ever cashing out.