I will not make a comment on whether to sell now or not but will comment on some of the points you made.
One thing that you should do is definitely talk to your accountant so that you can fully understand the implications of the new tax laws with regards to selling rental properties. Especially if they were once a primary, then you converted it to a rental for many years, then you tried to occupy it again as a primary and then sell it. Things have changed.
Another thing is to also watch out for the consideration of the rebuilding on the same lot. If you do add more then 500 square feet your home does get reassessed and boom, your new home will be assessed at current market value which is something that I am sure you are trying to avoid.
So really the question simply becomes choice of investment doesn’t it? I mean maybe I oversimplified but it seems to me that your question is one of where can I get a better return, using this current home as a rental, or using $x in an alternative investment, (where you got $x for the sale). If you feel that you can do better investing the $x, then the cash flow you will get from the rental combined with the possible appreciation or depreciation, then it is better to sell and then invest. Consequently if you feel that in 10 years the home will be worth more now then it is today and that worth would be more then the $x you would get from the sale combined with the appreciation of your investment then keeping it is the answer.
If the home is a place you really really love and you are okay financially then I would hold onto it.
