The problem with that is that when the top line goes cold, and they have and will continue to do so on occasion, the offense disappears with them. You're selling Gaudreau and Monahan short; both are capable of putting up points without the other.
And how often do teams have three similar high end players all on the same line? Which teams in this league, in the real world, can boast of that accomplishment? And moreover, how long would something like that even last in the cap world where true top liners make at minimum 6M, to a more current 8M+ in the post McDavid/Draisaitl era?
The best you can realistically hope for is two high end players and one complimentary piece.
I agree with you but i don't think we have the right players to pull it off. I am not expecting 3 70+ point guys on the top line but I think we can do better than Bennett and Ferland who have struggled to get 40. Its not so much that I think that either guy can't put up points without the other I question whether they can put up points with the options we have for the 4/5/6 guys.
I think if you can get another top 6 guy between Monahan/Gaudreau/Tkachuk and Bennett/Ferland/Versteeg then that works much better.
An example I will use since he was briefly talked about at the TD and moved would be Derick Brassard. While I think it would be best to try him out with Tkachuk and Bennett first if you were tied to splitting up Gaudreau and Monahan, lines with him there are a lot more reasonable.
Tkachuk-Monahan-Versteeg/Ferland
Gaudreau-Brassard-Bennett
Now Gaudreau isn't stuck as the only guy who can create on the line and has some offensive support. It also allows Bennett to be much more of a complimentary piece than a guy relied on to drive play at times. Now I think a RW would make more sense to split up Monahan/Gaudreau pairing since we would likely need Bennett to play center at that point. I am having a hard time thinking of a legit RW target but lets say James Neal.
Gaudreu-Bennett-Neal
Tkachuk-Monahan-Ferland/Versteeg
I think those are reasonable lines in both cases with Monahan and Gaudreau split. I still think the best option is to keep them together, especially with our current line-up and the bigger move is to get Tkachuk off the 3M line to create a secondary scoring line to support what would be the clear top line rather than two 2nd lines.