Apologies for the long winded answer, but.......
I was having a wider discussion in Shoutbox regarding our last season at this level, and what our stats were that year, and how we are in danger of mirroring them. In 06/07 season, we won 38 points off of a 38 game season, scoring 32 and conceding 55. Probably only 2 points & 8 goals away from what I consider to be our target this season.
We had the 3rd worst scoring record, and the 6th worst defensive record, only conceding 1 more goal than Spurs in 5th in the league. We were rarely battered that season, and were competitive in most games, eventually coming up short because we lacked the fire power. That season Hulse scored 8 in 29, Stead got 4 in 14, Nade 4 in 28, Jags got 4 in 38, Webber 3 in 24, Tonge 3 in 28 and Gillespie 3 in 31.
All those goals spread about the team and we were still were short; being 3 shy of the next lowest scorers. I don't think that we currently have 32 goals in this team, in this formation at this time, certainly not 40.
So in answer to your question, as part of the solution, we need an increased scoring threat & creativity from midfield, I don't think that Lunny offers that. He has shown himself to be competitive at this level so far and not disgraced himself, but if we are to persevere with the current formation, I would look to bring someone better in in JTW. What & who is better? Well I would look to bring in someone who possesses a skill set between Lundstram & Duffy. I don't think that we can go the full 'balls out' & Barry White on the wireless and play a Duffy & 2 upfront, but conversely I don't think that we can spend too much of the season playing a 'missionary with socks on' midfield 3 with Lunny in it.
If we chose not to continue with 2 up front, and play 4 in a diamond, then he may well be okay for our purposes, but that all depends on the person we deploy at the point of the diamond and whether the person ahead of him is scoring.