When we look back in history we can see that the churches that exclude lent from the liturgical calendar do not replace it with continual atmosphere of joy. For example, the Puritans abolished lent, but also removed Christmas and the joy associated with the celebration of Christ's incarnation. They removed from their lives other celebrations involving singing, dancing or recreation. This was not only a puritan trend. In the seventeenth century also Catholic Church in Madrid closed theaters, as well as the Protestants in London or the Orthodox in Russia.
In many churches rejecting Lent comes together with discarding the joy of Christmas. This explains why it is not about removing periods during the year, which interfere with the experience of joy. Removing the period of Lent didn't bring continuous joy of Easter, but resulted in continuous full-year leant. Churches that believe Lent in the liturgical year to be one of the greatest heresy - really fast all year round. This is because they say it's wrong to drink alkohol, go to pubs, listen to rock music or dance any time.
We recognize the lent in the same sense and for the same reason we confess our sins at the beginning of each Sunday service. This is the time of sadness because of our sins and wickedness. But this sorrow and lamentation should not suppress the joy at the goodness of our God. After the confession of sins we receive the assurance of forgiveness.
There is proper time for both the sadness and the joy. The time before Easter is the time to discover the essence of the resurrection and the blessings of the New Life. The spirit of Lent is a part of life of the church. Figuratively speaking, if we do not wear purple and ash for 40 days we may wear them 365 days a year.
At the end a little note. What's interesting - the church fathers are not recommended to fast on Sunday (except for confession of sins), because the Lord's Day is a day of joy.