If you play often just subscribe and pay the $15 a month. If your characters are maxed out and you don't care about stealing or killing randoms then don't do the DLCs. Morrowind is probably going to be a better experience as everyone will be new to it at the same time.
Morrowind will be packed for the first 4-6 months, and there should be a lot of fun play opportunities because of that. Also, you need Morrowind to make a Warden. If you want to try the new class that's a factor.
However, the 4 DLCs are fun. You might see if you can buy a physical disc for the gold edition for cheap before they all disappear.