Ok so I like many others had a problem with Miraak not coming out of ethereal state, but I found a way. It's very tough to do, but not too hard if you lower your difficulty.

Step 1: Start your fight with Miraak and do not hurt him more than 60% of his health left, anymore and he might go ethereal.
Step 2: When his health is decently less Dragonrend Sahrotaar (dragon you ride before you fight) and kill him so Miraak absorbs his soul.
Step 3: Get Miraak to about 80% health or so and cast Bend Will on one of the dragons flying above (be precise dragon shouts don't grow on trees) and kill him as well and Miraak will absorb his soul.
Step 4: Hurt Miraak some more and cast Bend Will on the last flying dragon and kill him; Miraak will absorb him and not have anymore souls to absorb.
Step 5: If you've done these correctly Miraak will have no more souls to absorb and you can kill him or damage him to where he teleports. Then Hermeaus will take care of him and you finish the quest line.

Please note that you should kill each dragon after a few hits to Miraak, do NOT damage him to where he teleports and turns ethereal before killing all of the dragons. i hope this helps everyone having trouble with this glitch and Bethesda is working on patching it.