Now Mercedes have very little chance of getting said dispensation, as they can't real prove unreliability.
Still rather be in Mercedes shows, but it does open up a very interesting avenue for Renault that pundits have already started chatting about. Basically as Renault is so unreliable, the engine freeze simply isn't going to affect them.
Every Merc car has broken down multiple times, how many times did the Renault cars break down before being allowed to have an update? Do we know the reliability fix wasn't something that wasn't causing a power reduction before failing and thus only put the engine back where it was?
Why do you presume every upgrade for reliability will increase power and why do you think the FIA will allow every upgrade on reliability grounds if they can see it's basically for power only.
Ultimately reliability is absolutely and in no way "proven" on Mercedes engines, nor has anything about the Renault engine been proven unreliable.
If one car can do 300 laps, and another 50 with the engine failing every time, is an engine "fix" required, or is the car that can only do 1/6 of the laps at fault through their own design? For all we know the Merc is seemingly reliable purely because it's only running at 90% to reduce temps, if/when a Renault car gets everything hooked up it could be spanking the Merc engine.
It also seems in a large part that a lot of Renault's problems were control problems, timings, issues. These can all potentially be solved and power increases can potentially be derived from simple software updates. The other fairly obvious thing to state is, I don't think RBR or Renault are focusing on power improvements right now, they are almost certainly working flat out on reliability improvements. Though the simple fact is that most reliability issues mean increased effective power. It's no surprised that the Renault doing the most laps is the slowest and best cooled. more reliable engine = ability to push it harder before failure. Improving reliability usually means you can use more of it's power.
They're massively on the backfoot, they can forget about going for wins until Europe at least, that's IF they have sorted their reliability out by then.
Renault could find one tiny little bug that has been ruining everything and once fixed the Renault could suddenly become the best engine on the grid. RBR may upgrade their cooling, make bigger side pods and find that as luck would have it, their existing aero package magically works great with bigger side pods and better cooling, they may suddenly be running with a cool engine and awesome aero. How likely that is, maybe not very likely but it's insane to rule out a car for X number of races almost categorically.
It might turn out that Merc's engine efficiency means they have to run significantly lower power to finish races with 100kg's of fuel while Renault have hugely better efficiency and will be able to run over a race distance with better overall power.
As I said above, it LOOKS like RBR are going to have trouble and be way behind, but we don't know where that baseline for the car is. They might end up months from getting the absolute best out of their car, but the best will blow Merc/Mclaren away by a mile, or they might suddenly get lucky get the very best out of the car by melbourne but the best their design can produce(be it aero or engine) is miles behind what Merc/Mclaren can do.
My general guess is, if they can improve cooling and maybe Renault can do some interesting stuff to the engine then maybe they can get a good amount of running done at the next test. However this will mostly mean that Merc/Mclaren who have already started to shift the focus towards aero/setup to find qualifying speed, most Renault cars are going to be focusing on getting the car working for a race rather than how well it can do in qualifying.
If they can sort out reliability quickly then I can see qualifying in the first few races being a huge problem, but the races may not be. We have no idea how the engines will stack up in terms of efficiency, ability to run over race distance, tyre wear, over taking. The Red Bull might struggle to make the top 10 in qualifying, but might have very good race pace for all we know.