I think its very obviously that Nintendo is going to do a slightly SLOW transition to bringing their mainly handheld IPs from the 3DS to Switch. some 3DS games still sell insanely well, just look at Pokemon breaking records a few months ago...
its pretty obvious Nintendo still wants to milk the 60+ million 3DS owners as much as possible so I would expect over the next year or two Nintendo starting to bring Pokemon/MonsterHunter/JapanRPGs/etc all mainly to the Switch.
the 3DS is still actually selling fairly well (at least based on numbers for the start of 2017) considering its like 6 years old or whatever... I get the feeling Nintendo doesn't want to cut off 3DS sales so that is why they're being conservative.
At any rate though if a Monster Hunter gets announced for the Switch in the next 6 months (E3?) and Pokemon Stars isn't just a rumor, then those two things alone would be a signal that they will in fact be consolidating things to the Switch coming up.
I just hope they don't feel pressured to make a lot of their IP released on the Switch considerably more advanced graphically than the 3DS- and the reason I say this is I do like at times when Nintendo has released a lot of solid games for handheld systems in a calendar year. I'd rather have a mix of innovative and NEW stuff (like Breath of the Wild) AND more chill things that should be quicker to develop (like an Animal Crossing or creative game like Mario Maker) come out a more frequent pace then a relatively barren calendar where they only release a few big things.
The nice thing about Nintendo's handhelds in the past have been you USUALLY do get a solid stream of games from them. So hopefully they continue this with the Switch. A lot of people would be thrilled with some upgraded ports of even 3DS games onto the Switch with better graphics and additional modes or whatever
but to the OP's question- yes, of course they should. They consolidate to one system. I thought that was the goal in the first place and frankly something Nintendo fans have been interested in for a long time. A big appeal to me potentially with something like the Switch IS the Hyrbid nature and potential of having the more advanced current gen (ish) stuff AND the more chill basic handheld games all in one box
