Purely playing devils advocate - and fully accepting that there is no substitute for experience - but WHO is better equipped to fly a MPA jet aircraft straight from their training - someone with 100 hours on a simple, single engine PA28 or similar, or someone who has spent that same 100 hours operating the aircraft they eventually fly, albeit simulated? The differences are absolutely ridiculously enormous. I would actually say that 100 hours PA28 would not equip you in any shape or form for the rigours of flying a commercial transport aircraft. [I caveat this with my only experience of the latter being my 50 or so hours in 737 sim on MCC/JOC]
I have no doubt whatsoever that someone with 1500TT moving to a jet would be significantly safer than any variety of 200hr newbie, but that's not on the menu in JAA land, so the question is whether SEP hours are worth a shiny fig when it comes to operating a complex Multi pilot aircraft.
From my experience - confidence in yourself and knowledge of the limits is more about knowing your aircraft than it is yourself. I would trust someone with 200 hours PA34 (bit more complex than PA28) for example, more than I'd trust an airline captain with 5000 hours, but no PA34 time if I had to be flown somewhere in a Seneca.
I doubt even Chuck Yeager would get into a brand new aircraft type and start throwing it around first flight....