The Somerset side finished seventh this season - and were well off the pace for much of the campaign.
"We simply couldn't field a settled side," said club president Greg Dyke. "We showed that, when at full strength, we could compete with the best in the division. But we were forced to make changes week after week for various reasons, especially before Christmas.
"Our form suffered, espacially away from home, and it took us a long time to win an away game.
Hopefully, we will have a good pre-season and be up for it in September. There is no doubt we must improve our away form if we are to be considered as serious title contenders."
Wellington have re-appointed ex-England and Gloucester second row Dave Sims as their player-coach next season.
Sims, who joined Wellington three years ago, is known to have been approached by other clubs, including Taunton.
But he has chosen to stay at the Athletic Ground even though his playing days are numbered.