Need Advice on Choosing Between Eguisheim, Strasbourg & Riquewihr

Of the places you list there is one we did not like, Colmar. Skip Colmar! The remaining three are special places to visit.
We used Strasbourg and Riquewehr as our bases and the trip was wonderful

Don't skip Colmar, I loved it.

Strasbourg is a city and really needs a minimum 1 full day.

Riquewihr and Eguisheim are both nice towns. Riquewihr seems to attract more tourists.

Here's a recent post about the wine villages that may help you.

Which of these wine towns should I visit.

Eguisheim can probably be seen/walked in about an hour. Riquewihr, a bit longer. That doesn't included stopping for wine tastings.

We found Selestat to be a good central location. It's on the main train line between Colmar & Strasbourg and the Unesco Bibliotheque Huministe is an overlooked gem. It has a copy of the first book to contain a map that applies the name America to the "New World." The guided tour is in French only but it's worth the visit. I think some of the information signs are in English. There are buses from Selestat to the Chateau du Haut-Koenigsbourg which is well worth a visit.

I also recommend a trip to Munster, the home of Albert Schweitzer. A lovely town at the foot of the Voges Mountains. The tourist office offers a free bike ride through the surrounding vineyards and towns. The Parc Dr. Albert Schweitzer has many species of trees including sequoias and Douglas Firs. During one visit I stayed at Le Grand Hotel and enjoyed watching the many storks in their nests on the trees on the south side.

It really helps to know when you're making this trip. There's a world of difference in these places between February, May, and August. Anytime before Easter I'd pass on Eguisheim or Riquewihr; they're pretty much shut down. And the idea that one can "see" Strasbourg in a day (or less) is ridiculous. I've spent 8-9 days there over the past three years and still haven't hit all the highlights. Colmar, like a lot of the smaller towns, is economically tied to tourism. It's attractive, but (in season) crowded, and feels fake.

My favorite place to visit in the area, which also does draw tourists, is the Sanctuary of Mont Saint-Odile. To me this is one of the "don't miss" places in Europe. https://www.mont-sainte-odile.com/

If you want a place nobody on this board ever talks about, that's attractive, has huge history, and is a short train ride from Strasbourg, spend 15 euro and an hour on the train and go to Wissembourg, which is all of the above, and the start of the French Wine Route also.

@KGC - Thanks for your input. We are visiting in late June. I understand that Strasbourg is a large city. We are only interested in seeing the old town and Petite-France. May be boat tour if we have time. We are not interested in any museums.