Newcastle opted to sack Bruce and brought in former Bournemouth boss Howe as his replacement, then subsequently backing him in the January window to the tune of £93m.
The relegation threatened Magpies signed Matt Targett, Kieran Trippier, Dan Burn, Bruno Guimaraes and Chris Wood to boost their chances of survival.
Merson is not convinced by the business Newcastle did last month, believing they lack firepower, and insists if Bruce had been the manager signing the same players then the fans would have been unhappy.
“Only time will tell regarding Newcastle’s transfer window”, he wrote in his Sky Sports column.
“All I can say is that if Steve Bruce had bought in all these players there would have been uproar, and I think that tells you everything you need to know.
“If they’d have managed to get Jesse Lingard in that would have been the player with the X-factor they needed, but that hasn’t happened.
“They haven’t bought in that player with a real point of difference in the forward positions.
“They have bought in players to be more solid, but it is okay being solid, you need that X-factor as well, and I think they may struggle putting the ball in the back of the net”, he added.
Newcastle face an early test of their January business on Tuesday night when they welcome Frank Lampard’s Everton to St James’ Park.
They have won just one of their eleven home league games this season and have not scored more than once in any of their last nine league games.
