The Owls suffered just their fourth league defeat of 2019 against John Eustace’s men after Josh Scowen and Matt Smith’s strikes cancelled out a Michael Hector penalty.
It was a poor performance from the Hillsborough side that featured four changes including a first start for Kieran Lee in 15 months.
Reflecting on his team’s performance, Bruce said: “It was interesting, lacklustre, end of season. A bit like a friendly.
“I have to say the first half last week and this week have been particularly difficult for me because obviously we have lost that edge to try and get in the play-offs and once that was sealed and when you don’t do all the basics right then you get punished.
“We got punished today for being sloppy. It certainly looked that way from both teams and it burst into life in the last ten minutes.
“There was more in the last ten minutes than there was in the first 80.
“Overall, they have done very well but to finish on a defeat, the last week in particular has been particularly difficult because it’s been taken away from us, what we could have had.”
The end of season result leaves Wednesday 12th in the Championship table after a disjointed and inconsistent campaign overall.
With attention already turning to the offseason and summer transfer action, Bruce was adamant that he will set the bar higher next season.
“We’ve had a good three months when you look at it but we have got a big job ahead,” Bruce said.
“We have got four players who have got to resolve their futures and eight or nine out of contract so a big summer ahead in terms of what lies but we will have to box a bit clever with our signings.
“The vast majority of the players in the squad here have been here two or three years and haven’t been able to do it but have come close twice is not easy.
“As I’ve said, over the summer it’s about getting a team that is capable. Mediocrity is 12th and I’m not going to accept that.”