Streamlining, by definition, is something mostly positive. It means simplification.

In the past though it was used, by Bethesda itself, to justify the removal of some very important parts of TES.

So, while it's still early, let's not sit around waiting for something else to be "streamlined" and instead try to be bloody vocal about it.

1) Spell making and the lost utility spells - Bring them back!

Spell making was an amazing feature, allowing you to be creative and brought the magic classes' gameplay in TES to a whole new level. It was killed off in Skyrim with what seems to be the poorest excuse/justification a person can possibly conceive:

The end result was getting a small number of spells with set characteristics, which did not even scale properly.

As for spell making, we watched NPCs "perform" it at the college and we even got quests, helping them to test their newly made spells adding more insult to the injury.

Spell making is not spread-sheety. It is scholarly. It is immersive and RP friendly. And most of all it is an amazing addition to gameplay. For the love of god, put it back in the game.

2) Weapon variety

Similarly to spell making, having a larger variety of weapons in the game, adds a ton to the gameplay and replayability.

Spears, halberds, crossbows from Morrowind and flails from Daggerfall. If they appear in TES VI with unique perk trees and each offering a unique combat experience while using them or while facing the enemies who use them, they will enrich the game immensely.