Prior, the tour vice-captain, said Pietersen's ability should have made him "the best England cricketer to ever walk this planet" and the decision to dispense with him would not have been taken lightly.
When asked if the dressing room would be a better place without the South African-born batsman, Prior replied: "Yes, it will.
"I think one of the biggest things they (the ECB) want to rediscover is the value of playing cricket for England, the honour and the pride you need to show as an England cricketer.
"And they only want people in that dressing room that are going to be passionate about England winning and performing," said Prior during a Q&A session at a cricketing event in Dubai.
Pietersen was released from his ECB (England and Wales Cricket Board) contract earlier this month in the aftermath of the 5-0 test whitewash by Australia.
The ECB said captain Alastair Cook needed to be able to trust and rely on the support of all his players.
Pietersen scored 8,181 runs in 104 tests and 4,440 runs in 136 one-day internationals but was never far from controversy.
He was briefly dropped in 2012 following media reports he had sent "provocative" text messages about England players to members of the South Africa squad during a series involving both teams.
More reports surfaced about Pietersen's divisive role in the squad after the latest Ashes series.
Prior, who has played in 75 tests and hit 3,920 runs at an average of 40.83, missed the last two tests of the Ashes series after being dropped because of poor form.
He said that being omitted when he was vice-captain, in the middle of a big series, "quite literally wrenched my heart out" but added he was determined to regain his place for the home series against Sri Lanka and India later this year.
"I have more passion now than I have ever had to get back in that team, turn things around and get back to winning ways," Prior explained.
The wicketkeeper also predicted that opening batsman Cook would bounce back in style from England's humbling in Australia.
"He will break records and he's a phenomenal cricketer," said Prior. "He will score the most runs for an Englishman in test cricket, no doubt, and he's a phenomenal bloke as well.
"To read some of the criticism he's got has just been incredible, as anyone who knows him respects him.
"When it comes to captaincy he's a big enough bloke to admit he's not the finished article yet. He's still very young in his captaincy and he needs to learn and needs to grow into the position," said Prior.
"There are certain things I think a captain needs. I think being such a nice person is one of the things which doesn't stand him in good stead as a captain and the best thing about him is he accepts that and he knows he has to improve."
England begin their limited-overs tour of the Caribbean when they meet West Indies in the opening game of the three-match series of one-day internationals in Antigua on Friday.
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