The issue is three parts:

1. Pricing all items sold directly for currency (no engrams)
2. Clearly indicating the availability of items
3. Obtaining the items without paying for them

1 and 2 are still a problem in Destiny even if you are going to support the game and buy them.

3 is not an "incredibly tedious grind" (There ARE incredibly tedious grinds in Warframe! Grinding currency, however, is not one of them.)

Even if you exaggerate and suggest that grinding currency is incredibly tedious, that still leaves 1 and 2 as things that are pretty shady and hostile tactics we have to deal with from Bungie, that DE has proved aren't necessary to have a profitable, sustainable game.

If you'd like to talk about the incredibly tedious grinds in Warframe I'd be glad to, there's plenty to complain about.