In a vacuum, #1 overall without a second thought.
This year, with no solid clear-cut #1 a la Crosby, Stamkos or Tavares, I'd be just as comfortable keeping Tanev and the #6. If the deal's there, go for it but this season I can't see the dropoff from 1 to 6 being as dramatic as it would be next year or in years past. For MacKinnon or McDavid? Hell yes. For Ekblad or Reinhart...not quite so sold.
The price for McD will be much higher than for Ekblad. If Ekblad truly is a franchise #1 D-man in the making, Tanev and a 6th is dirt cheap. As mentioned above there are D-men ion the UFA market who can replace him. I get the feeling he isn't if the Panthers are willing to let him pass and accept Tanev as a worthy replacement. This is, of course, you believe they already have a franchise #1 in their D mix.
There are several forwards in the top 10 with the potential to become great, but they have just as big a chance to bust. So given the ups and downs as I see it, if the Canucks believe Ekblad is big upgrade over Tanev, they are trading him and the 6th for a D-man they can't get by holding on to the 6th.
If they do this for Reinhart, it might be a big mistake. I haven't read any scouting analysis that puts him in the class of a top performing Sedin. Maybe they think a top 6 forward is good enough and Tanev and a 6th is not too high for that. I doubt that Vancouver could offer this deal to any team for one of their legit top 6 forwards and get it. A couple days and we'll know for sure and the second guessing begins from those who don't like the deal that was done.