I would actually love to see 4 tests matches start on the same day/within a week or so of each other, with a long break in between them. Builds up anticipation for each match, and the period of time for that week or so within which the games are being played will be quite exciting.
4 matches in 4 time zones...West Indies, England, Asia, Australia/NZ. Some matches in South Africa too, and maybe hold a few token matches in the USA.
And this would be a great way to introduce new sides into Test Cricket. If there are 2 divisions of 6 sides each, you can have 6 matches running simultaneously in 6 different locations. And you can add in 2 new test nations. 2 out of Ireland/Scotland/Kenya/Canada. Maybe a USA team if you are going to play a few matches there, might gather some interest.
So this way there is no overkill as all matches have meaning. Cricket can still be played all year round (just in different countries...they can be called the 'Asian Leg' or 'European Leg' or 'Oceania Leg'...), and with nice breaks in between to prevent burnout. Only the best players play (since the Top 6 sides are in one division and can't afford to rest key players a lot), I think it's a good idea.