Are we talking about the same Tiberi who finished 42 minutes down on Uijtdebroeks in last year's Vuelta (his best GT result)? Why are his goals/wishes so much more realistic than Uijtdebroeks'? Uijtdebroeks already showed he can battle for GC 3 weeks, Tiberi hasn't. Uijtdebroeks finished 7th in the Tirreno, Tiberi 27th.
I was also fairly surprised when Tiberi claimed he had the realistic goal of finishing top5 in GC (and dreaming of a podium).
But considering his limited experience as a team leader and the fact Bahrain elected to send him as a captain while having both Caruso and Poels available, his numbers must be very good at the moment. Otherwise the team wouldn't be so confident.
Note that Tiberi told me his recovery is excellent and during last year's Vuelta he felt better and better as days passed. The route is certainly on his side, with the amount of TT kms and the abundance of 6-8% climbs, since he doesn't fancy particularly steep hills.
I'd say right now fans and bookmakers favor Tiberi over Uijtdebroeks partly because of recency bias. It's true that Cian was much better in Tirreno, but Tiberi has steadily improved race after race and looked excellent in TotA.
Everything considered, I reckon a top10 should be reachable for Tiberi in this field. Anything more would be a great result in my eyes. Uijtdebroeks likely has a higher ceiling but I'm not very confident after his first mnths with Visma.