I never looked at him this way but after checking his results I gotta admit there's some truth in your statement: he tends to struggle in hard mountain stages (although there are exceptions).
On the other hand his recovery (let's call it consistency if you wish) looks questionable too. He never managed to contend even in short and relatively easy short stage races like TA.
He's much better on hills than long climbs, that's for sure. Which brings us to the point I was trying to make: he's a good enough climber to make the cut on Sormano, Civiglio and so on. We're not talking about a multimountain Giro stage in the Dolomiti.
I agree on your point on consistency.
However I'm not sure he would be a contender in Lombardia. He might have been this year due to the lesser field and him being in shape, but I think he would have struggled on a regular edition. His best placement has been 23rd two years in a row. Maybe he wasn't able to properly peak for Lombardia before, but I can't really see him performing there.
On the contrary, I think he could easily crack the Top10 at Fleche Wallone (despite his best performance being 27th) and even win Liege someday (i don't think his second place last year was a fluke).
PS: Hills in Lombardia are way harder than those at LBL. LBL climbs can be managed by "Ardennes" riders, but Lombardia is more suited to proper climbers.