I think the design of the interior is perfectly fine - it fits their ethos and their general style and I don't think they need to make it more "complex" to be competitive. I don't think they need to add buttons or dials to the interior, if someone prefers an interior that's more busy then I don't think this is the car for them and that's okay. I think this style of interior appeals very well to their target demographic, namely people interested in technology and pressing electric vehicles forward.
I think quality and general features needs to improve though. I'm missing the Alcantara on the dash now. I want vented seats that actually work. I want seats that are as comfortable as my BMW or Mercedes. I want a HUD. I want a media player that doesn't fight me every time I get in. They're a new car company so I give them passes on most of these things, but that won't be the case forever and I think they'll need to catch up on some of these things to progress forward.
@ReturnZero your post pretty much sums up my thoughts as well. Only differences being that I HAVE the Alcantara on the dash and really, really like it - though before I got the car I was thinking it was a negative...but it's totally grown on me. And I feel the current (3rd Gen/Premium) seats are very comfortable. I have the Ultra White with PUP.
Agree with everything else - I like the minimalist design aesthetic. Coming from multiple BMWs (pretty much the only cars I've owned before the Tesla over the last 15 years or so), the Tesla interior is definitely "different" and it doesn't conform to conventional thinking about what constitutes a "luxury" car - lots of wood, angles, chrome, leather everywhere, multiple textures, lots of buttons, etc. I'll admit the initial feeling I had of the interior was that it is was underwhelming. But now I am into it and see it as minimalist. Like iPhone vs Blackberry. Remember the talk when the iPhone debuted and people said it couldn't compete with the Blackberry (especially in business) because it lacked a physical keyboard, scroll wheel, etc? And everyone I know ages 25-35 LOVE the interior and think it is far superior to "traditional luxury" interiors from BMW, Lexus, etc.
The things that need to improve for the interior in my opinion are mainly around the console and cup holders/arm rest. It takes up so much room but functionality is lacking. Looks like the Model 3 has the superior center console by far. I also think the door panels need to be reworked. They intrude too much into the front seat space (i.e. they are too wide). As for the handle to activate the electronic door opener being in the upper corner of the door....I've become used to it, but every passenger asks "how do I get out?" when riding in the car for the first time. Might be made to be a little more traditional. Again, seems like they have done this with the Model 3 (to some degree) already.
I drove my BMW (650i) this morning - have to drive it once in a while to keep the battery from dying and the fluids/seals good...that's about the only time I drive an ICE anymore (well, that and my wife's SUV). Two things about the interior of the BMW struck me today as things I'd like in the Tesla - HUD and a slightly smaller (more sporty IMO) steering wheel. And of course the aforementioned center console - I think the Tesla's center console is perhaps the least functional one I have ever seen, so virtually any car will beat that part out. HUD is super useful. Imagine a HUD with the representation of the autopilot stuff - the adjacent lanes and vehicles. Or nav directions. I love the HUD on the BMW. And with Tesla being software-driven and OTA updates - HUD would be something non-static and could evolve and change. That would be exciting. Smaller, more sporty steering wheel would help (a little) in making the Tesla feel slightly less boat like. I haven't measured the two wheels but I can definitely feel the BMW's wheel is smaller in diameter and, in my opinion, feels better than the Tesla wheel in my hands.
That's about it. I like the 17" display and hope they keep it integrated and vertical. Of course, the computer running it and the screen itself needs to be upgraded to be faster and more responsive. But otherwise I like it where it is.
There are small details like the glove box cover feeling flimsy that I suspect an interior refresh may also improve on. And ambient lighting and reading lamps, etc could be improved. And I think they will be. So, in summary, although I think there is room for improvement (especially that whole center console!) in the interior, I don't think it will be the deciding factor for too many people who are considering a Tesla. The appeal of a Tesla is more than the sum of it's parts. But even if it's a minority of fence sitters that would be swayed, a refreshed interior that still stays true to Tesla's minimalist ethos will be likely welcomed.