And the ex-Fratton favourite was backed up by Black Cats legend Kevin Phillips, who believed the Blues boss got it wrong in his attempt to try to wrestle control of the semi-final away from the Wearsiders.
Both Taylor and Phillips were acting as pundits for Sky for the crucial second-leg tie at PO4.
The game finished in a scoreless draw – allowing Sunderland to progress to the League One play-off final at Wembley, following their 1-0 win at the Stadium of Light in the first leg.
The Blues desperately needed to score to keep their promotion hopes alive, and had tested Black Cats keeper Jon McLoughlin twice through headers from Gareth Evans and Hawkins.
However, as they toiled in their efforts, the latter was substituted on 68 minutes and replaced by on-loan Vaughan as Jackett attempted to find the breakthrough.
The Pompey manager had already brought on Jamal Lowe to replace Viv Solomon-Otabor in a bid to breathe fresh live into his side’s attack.
But the Hawkins/Vaughan swap was questioned by both Taylor and Phillips.
They were in agreement that the giant striker was unnecessarily sacrificed at a time when the Blues needed a physical presence and numbers in the Sunderland penalty area.
Giving his post-match analysis after the final whistle, Taylor, who made more than 200 appearances for the Blues said: ‘I think, needing the goal, they (Pompey) didn't get it and Kev said that Sunderlend defended well, but they weren't really tested often enough, I don’t think.
'I think they (the Blues) will be disappointed.
'At times the quality wasn't good enough.
'The fans tried their best to get behind the team, but ultimately the team just didn't seem to gel as well as it probably could and should have.
‘We saw Portsmouth for a period of the game trying to have a go and get at them, but it wasn't often enough.
'And I think every chance Portsmouth had actually came from a cross into the box – and both Kev and I were quite surprised when OIli Hawkins was taken off, because he's such a threat with those aerial battles that he wins.
'It was a shame.I thought, It petered out a bit in the end.'
Phillips, who scored 113 goals in 208 appearances for Sunderland, said Vaughan should have partnered Hawkins up front for the remaining 22 minutes, particularly with Lowe’s threat with crosses from the right wing.
'I thought no team was going to carve each other open with good play,’ said Phillips.
'A goal was always going to come from a cross and we were so surprised (by the substitution).
'Bring Vaughan on and leave Hawkins on.
'Two players who are good in the air – get it wide and get crosses into the box.
'You need to score, Portsmouth had to score to have any chance to go through.
'It surprised me. He (Jacket) brought Jamal Lowe on at the right time, so he's winger who is obviously going to drive at people and get crosses in.
‘But to bring off a centre-forward that's six foot four, who's dominating quite a lot in the air, has had chances, really surprised me.’