The more I think about it, the less I like the Joy-Con controllers.  As has been discussed ad nauseum, they are too small and the buttons arranged too awkwardly to be used as single controllers.  Also, that grip controller looks rather strange, and I think I would just use the pro (yes I plan to buy regardless).

Now the thing that bothers me is a lot of Nintendo fans and the writers of Nintendo sites seem to agree, and write off the concerns by saying they simply won't use these features.

However, this is the essence of the hardware design.  Think of the design compromises they had to make to pay for and make room for 3 batteries and wireless radios, and two side ports, just so they slide off for no good reason.  Also, with extra moving parts, it becomes less durable, and opens up the possibility we would need to buy more peripherals down the line.  In other words, if you don't plan to use the Joy-Cons as stand alone controllers, the fact that they are removable makes the console worse, not better.

I feel it would have been better if the switch simply had the sides built in and come bundled with the pro.  The cost of the pro would easily be off set by the decrease in costs of two batteries, wireless radios, and side ports, plus the cost of the grip center piece.

I agree. Simple is often better, especially when the added value of something like this is going to be relatively low. How many games are going to function well with the mini-controllers? I think it's an added cost with little upside. I'm pretty sure they did it to sell more consoles, considering how heavily it was marketed in the teaser, but I really doubt if it will make much of a difference in units sold.

It's not a huge deal either way but I do think it will end up like the 3D on the 3DS, where no one is talking about it after awhile.

You don't think a single piece of hardware with 2 extra batteries, 2 extra wireless radios, and 2 ports adds any costs?  It made the unit more expensive, less ergonomic, and/or they passed on hardware features they otherwise could have implemented.

I feel like there is more to the Joy-Con than meets the eye.

I was thinking maybe they will release multiple joy cons which have the positioning of the buttons different to each other.

But of course I cannot comment on if it is comfortable or not but many are like what you said, have doubts on it.

Best thing is to wait to get a feel for them for ourselves. And maybe the final deisgn will be different and maybe better.

Its a convenient gimmick that will probably do well with kids. I don't see the problem as long as they're available to buy separately as accessories and we don't have to go through Nintendo's bs.

I agree about the button layout of the joy-cons in how the top and bottom parts are directly aligned with each other, especially the right side.  This isn't much of an issue on the left side since the analog stick is out of the way on the top but on the right side, I can easily see someone constantly hitting the analog stick when they try to press any face button.

They do look really small to hold, but there aren't extra moving parts as compared to a normal controller

I'll wait till we get more info about this before I give my final thoughts