At first: Welcome on the forum. 
Second, it looks like it you know your way in photosoftware on more then one brand and type.
Good pointers about strenght or losses when implement a DAM in a rawconverter/developer.
As i wrote somewhere else i am not a heavy DAM user or a target to sell me one.
Searching though archive of raw files can be a pain if you don’t know date’s.
So a DAM can help with this.
One thing i can’t oversee but i think it can be a issue is when having a DAM guarding your rawfiles and a DAM guarding your endproduct (jpeg) could this bring a conflict in database?
(i understand that the sidecar xmp file is transfered from raw to jpeg so all original metadata is present in the xmp of the jpeg.)
I wouldn’t think of using dpl for watching and organising my finished jpegs. I use PSE for this. suits me fine.
So i light tag and search function would be fine.
If DPL’s tagging is written in a XMP and copied in PSE’s DAM , it will speed up my cataloguing i think.
multi select, change “location field” or “GPS field” that would be a nice tool.
In PSE i can make tags and multi select to apply this tag, so if i can choose to do this in DPL or afterwards in PSE without any trouble well, bring on that DAM in DPL. Unless it slows my workflow of developing down by processingpower then it could be annoying if i can’t turn it temporally off to speed up screen changes.
(you see i am not a skilled DAM-er 
)