I did write that on the back of the brisbane loss and I'm generally glass half empty these days too, but I still think it's true. To be clear, I'm not saying we need 4-5 Martin/Kelly quality players, that Merrett needs to be our 5th best midfielder.
My fundamental argument is that generally when a team has thought they were just missing one really good player, the truth has been that they were missing more than that. Maybe we're different, maybe not. Anyway, here's my reasoning:
First, I didn't say 4-5 midfielders to our best 22, which is an important distinction. I think our depth needs improving, and a lot of our current depth is likely to be gone next year (Bird, Howlett, Stanton, Hocking).
Second, related to the first, our injury record in the midfield this year has been excellent. We've lost very few games from our first choice midfielders to injury. I'm not saying we should plan on crippling injuries, but at the same time it would be foolhardy to assume a better than average injury run.
Third, we will need to replace some good/very good players over the next 1-2 years, and replacing those players only keeps us level, it doesn't improve us. For example to keep our best 22 as good as it is for next year, we need someone as good as Watson's current form. That's not his peak form for sure, but it's still decent. Goddard is near the end too, even though he's playing on next year.
Fourth, as I've discussed ad nauseum in other threads, I think we have some issues with over-specialization in our midfield and the only solution to that is to bring in some all-round players. That's a structural issue which by definition cannot be fixed by a single player.
Now, obviously we have a bunch of young players in the VFL, but until they're actually playing regular senior football you can't just assume they're going to be good players. If Laverde, Mutch, Begley, Langford all establish themselves as first choice midfielders then, yup, one more really good player will probably take us over the top.
As for how we got about achieving it, it's really difficult, and if I was put in charge I'd make a hash of it. I'd maybe try trading down the order a bit for multiple picks. Lower chance of getting a good player than using a decent first round pick, infinitely higher chance of getting multiple good players. I'd definitely look more at trading a pick for a player than multiple picks for a player.