Look I understand what you're saying but if you're looking for a physical presence or a ball-winner in the midfield Gomes certainly doesn't fit that profile. He has good physical attributes but rarely have I ever seen him showcase them. Workhorses are expected to provide some control and defensive structure to the team while their techincal ability going forward isn't as important, but Gomes can do neither of these jobs which renders him useless on the pitch.
I too am not an advocate of playing Coutinho-Iniesta-Messi-Suarez-Dembele on the pitch at the same time as it would compromise our defensive shape and would lessen our control in the midfield, but relying entirely on Messi is not a good thing either. You mention how Messi alone is worth 3 players in attack and I would tend to agree, but being overly dependent on him is what has gotten us knocked out of the CL the last few seasons. Yes our defense has not helped either, but other than that fluke 6-1 we couldn't put any goals past Juve in 16-17 and were only able to score 2 goals against Atleti in 15-16. So what happens when you get so dependent on Messi is that if good teams find a way to shut him down or he's off form we'll struggle massively to score and that's why it's so important to have a few other creators on the field.
If we face a team like City or PSG in the CL they'll take Messi out of the game by putting 3 men on him and as good as our defense is they'll still find a way to put a couple goals past us considering they are two of the best attacking sides in the world. So Messi is suffocated in the midfield and we're playing elite opposition that can score, then what? We can't rely on a midfield of Iniesta-Busi-Paulinho-Rakitic so spark much offense. We'll be static and most likely lose or draw the match.
This idea of relying on Messi and Iniesta alone to generate all our attacks and defend with workhorses in midfield only works if we score first. That way the opposition opens up and we get more spaces to play off. We cannot chase a match with the midfield you desire and to win the CL you'll have to comeback from down in the tie many times. Notice when we've conceded first our record isn't all that great?
Celta in the league scored on us first, it ended 2-2
Espanyol in the Copa scored on us first, they won 1-0
Espanyol in the league scored on us first, it ended 1-1
Valencia in the league scored on us first, it ended 1-1
Atleti in the league scored on us first, it ended 1-1
We struggled to comeback against Alaves and Getafe both of which scored first on us and we barely won those matches 2-1 with late goals.
The team you dream of us playing simply cannot chase matches, it may work in the league and cup where we are much superior to most of our opposition but against clinical teams in the CL it will be tough unless we score first.