It would be a PR disaster for Intel if the median improvement is 5%. I'm sure Intel knows that and they will do their best to at least target 10%.
Since when have Intel's desires and their ability aligned? They haven't put in the engineering to get 10%, so they won't get it.
Does it even matter on desktop? Some leaker claimed MTL on desktop is a low-midrange CPU and ARL-S will be the higher end replacement for desktop.
That still leaves them a ~2 year gap in which all they'll have is Raptor Lake.
Might hang on in raw performance against Raphael, but that's a significant gap in efficiency and platform features, and Raphael-X will be the clear performance champion for most of that time period.
But then what happens when Arrow Lake comes out? Let's say Lion Cove does get 10-20% IPC over RWC. Is that enough? It'll be up against Zen 5, with probably a similar, if not greater increase. And that's ignoring the V-Cache models that should be becoming more high volume by then. Seems to me like Arrow Lake won't be enough to fundamentally change Intel's competitive situation. Might take Panther Lake, or even Nova Lake for that. Feels like a repeat of the Pentium 4 days, in some sense.
Ironically, Intel's biggest advantage with Arrow Lake vs Granite Ridge might be a process advantage, regardless of whether that's from N3 or 20A.