Turbo-props and jets are different - period.
I have flown as FO and Captain of turbo props and as FO and soon to be Captain of a Jet.
One does not qualify you for the other.
Jets and swept wings require more attention in crappy weather than a turbo prop does, and for that reason, on stormy nights with strong crosswinds when I hit the stick off the stops on the electric jet that I pine for my old turboprop back!
Another thing about Jet flying is Energy management, and that is a skill that is best learnt from the RHS with a safety net beside you in the LHS, and the ability to hone that skill very much comes down to the individual, and even the most experienced guys still get it wrong from time to time
Ok, big deal, you Go around and try again, next thing about being on a jet is the alarming rate that a Go around and subsequent approach uses up your fuel, so careful energy management and fuel management are areas that a prop captain may use on his a/c but IMHO, having flown both, the Prop can get you out a spot easier than a Jet can.
Then there is the differences between Jets. Again I have flown both the bus and the 737 and they are very very different, the bus looks after you in lots of ways but it can still, and one day when your least expecting it, be flown as a conventional a/c and thats when experience on types like the 737 will serve you well, although rusty you will have seen it before.
Taking this argument up to the next level, I don't think two years in the LHS at EZY would qualify me for DEC LHS at the like of Virgin or BA LH. Bigger jets, more engines and of course long haul experience of which I would have none.
In summary I belive in the career ladder and the more rungs you visit on your way up, the more rounded Jet Captain you will make.
But to confirm what others have said any future recruitment of DEC's at EZY is a very very very long way off.
Best of luck, but I think if you have a LHS Q400 job at a base where you want to be and it seems secure, for now, if it were me I'd be staying put. Sometimes it can be hard to see how green the grass is on your present side of the fence!