Unai Emery, who was sacked by the Gunners earlier this season, admitted earlier this month that Arsenal wanted to sign Wilfried Zaha ahead of Pepe.
Pepe has six goals and eight assists in 32 matches in all competitions since his £72m move from Lille and Aliadiere believes Arsenal should be getting a lot more for their money.
“I saw what he did with Lille last season and he is an amazing player,” Aliadiere told Goal. “So, I’m not denying his talent.
“What I’m seeing, though, is the most expensive player in Arsenal’s history and even if you don’t want to think about the money, the fact is that money is, unfortunately, a big thing in football.
“And when you spend that much money on a player, you expect more goals and you expect more assists.”
Aliadiere added: “If you look at his stats, I would say he has had an alright season.
“Now, obviously it is not easy, as I know having been there, but the thing that has disappointed me a tiny bit is his decision-making during games.
“For a player who cost £72m, it’s the simple parts of the game that sometimes I see him lacking. And that’s what I pick on a bit.
“Yes, he goes on a good dribble and goes through two or three players – that’s amazing. But when you have (Pierre-Emerick) Aubameyang on your left and all you have to do is pass the ball in the right spot, and instead cut it back at the wrong time, that bothers me. And I’ve seen that quite a lot from him this season.
“Maybe with confidence, with more games, that will improve. But it’s that sort of thing – when he switches off and seems to lack concentration – that gets to me.
“That is something you can’t really have with top, top players who come for that sort of money. The easy stuff has got to be done properly.”