|Lets look at your question for a moment from both aspects. First of all, someone with no time on any of the types you mentioned, and with 1500 hours PIC as an instructor, is not very likely to get the left seat initially..at least not without training and.....100 hours PIC US. So the comparison begs the question.
Having said that, the question should not be an either/or. Because the above should not jump into the left seat, does not mean that someone with 100 hours or so of PIC should, when their total PIC then is about 200 hours be given command regardless of how many hours they have set in the left seat and how valuable they found the time..
A better question would be this.
Would a pilot with 1500 PIC as an instructor and 1000 hours of fo time on one of those types, be a better left seat canidate that someone with 100 hours PIC and 2000 hours of FO time.
Generally, I thnik the former would be better. But alas, as I posted before, the real world of small operators does not generally preselect for command qualitities which means it is more about the individual. Also, if companies went the former route, they might just have to pay a decent wage for FO's, and one of the primary reasons they are running FOs in some small scheds is because the aircraft dont have autopilots and an FO is cheaper than installing and maintaining one. The problem of course, is the FOs, being human want to do more than steer the aircraft.
One indicator I like to use is how an FO views their time with regard to upgrades. The answers in an interview are surprising. Some will detail their knowledge of the aircraft and admit they need training/practice/experience as a Captain. Others will go on about the welath of experience they have obtained as an FO and make the jump to conclude that will make them great command material.. The ones who put to much empahasis on the quality of their FO time are the ones to be concerned about.
Here is a thought. Years ago, when pilots were getting night ratings they did the instrument portion at night, and tried to log it as both instrument and night..Whcih they could do..BUT..TC would not allow them to use both for the rating..One or the other. All TC needs to do is put out a policy that PIC undersupervison will not be considered to be PIC (as it really is not, after all, a post solo student could be said to be logging PIC under supervision some of the time!), or that it can not be used for the upgrade of a license.. No big change required and I think you might just see it happen in the near future. After all, with an ATPL one we could see a Captain of a large aircraft in command with a totatl of 250 hours PIC...just a bit scary. Fortunately, the Canadian majors dont hire 250 hour pilots for the right seat (yet) so for the time being the risk will be restricted to the budjet cutting smaller operators and the FO's who will whore themselves out for less than minimum wages.....after all, as I have heard countless times...If they demanded more money there are 10 others behind them who will take the job....gotta love the reasoning.