I think the main reason he hasn't played is while under Harry, we were USUALLY (I think, or I'm pretty sure anyway

) winning games by the time he came on, so Harry brought him on to shore things up. This season, we seem to be chasing a goal a lot of the time so Jake isn't the type of person you want bringing on, hence his limited time I reckon.
I'd love a top class creative mid (Modric & Rafa love child would be amazing

), someone like Erikson would be more than welcome but I don't think Levy will shell out for another CAM when we have Sig, Holtby, Dempsey plus Mousa and Carroll who can all play there.
I think we definitely need 1 striker, if we get top 4 then we'll need 2.
Townsend can add the wing cover/ competition IMO.
I think we also have to take into account, and although I think it's unlikely that AVB
MAY not be here if Madrid and Mourinho part ways and do indeed chase AVB as his successor. He did say in an interview he's "focussing on next season with Spurs" etc but we'd be stupid to think someone would turn Real Madrid down if the opportunity arose.
AVB will be here mate. He's just hinted in an interview that he'd like a contract extension, and apparently it's being looked at according to the ITK's. - Same for Bale supposedly.
Rumours are circulating that Ancelotti is taking over at RM.
I think you're probably right regarding the CAM role, but unfortunately there's not been enough goals from those players. (can't really count dempsey as that role as he's played wide also)
Not sure where the best fit for Holtby is at the moment. As i've said, I think it might be slightly deeper.
It hard to say, but i think we might have to be slightly ruthless this summer with 1 or 2 of those players, regardless of whether we make the CL.
It's all well and good having large numbers, but you've got to have quality to either get you into the CL and/or to be able to compete in it. For me, there's things missing from that group.
I still don't understand Sig's role in the side. His preferred position is being occupied by Bale which has left him playing on one of the wings, which isn't ideal for him, or our style of football. i think he's played well over recent months considering, but something inside me still says that it's a "make do" situation. We can't have that if we're genuinely serious about Top 4.
The same goes for Dempsey. He hasn't worked out centrally, so he now occupies a wider role and does ok. But he's not ideal either. Again, it's a "make do" situation.
Our squad and playing positions are messy and just... well... not quite right.
We have a winger playing as a striker (Bale)
An attacking midfielder playing as a left or right wing forward (Gylfi)
someone who was signed as a striker playing as a wider option (Dempsey)
another number 10 operating out on the left at times (Holtby)
As fans we seem to have become accustomed to thinking "ah well, that'll do", because we're forced to to think like this by the club we support. There's always some sort of dilemma. It all stems from the striker situation, but I'm no going into that again.
I think there's more work to be done in the transfer window this summer that we think.
Bale going central has worked well for him personally, but it's crippled other players and left us with no shape on so many occasions. The likes of Sig and Holtby haven't had a chance to shine in their natural position. It's not Bale's fault obviously; he wouldn't be in this position if we weren't so desperately short up front.
What I'm getting at, is that we need to get some balance.
Those midfielders you listed above lack goals, for one. If we say that TC isn't a realistic starter just yet, we also lack creativity. Also, with the exception of Dembele it's hardly the fastest group either.
This is hypothetical obviously (before anyone throws a tonne of bricks at me) But the sale of Gylfi and Dempsey would more or less fund Eriksen alone. It allows us to have options. Eriksen and Bale can both play central, Bale and Townsend can both play left. Therefore we can mix it up, without losing balance, but still have a player in the side who can create, and score goals. The lack of goals from out midfield is a big problem at the moment.
We've also had a lack of depth this season as i have said. With all the games next year as well, it's important that we've got competition for places. I honestly believe that Holtby could be the replacement for Parker, which again gives us some versatility and rotation with Sandro/Dembele/Holtby.
Then it's just a young up and coming player to give Lennon competition.
AVB likes to rotate, but this season the depth hasn't been there and nor has the quality. It's a massive factor in CL qualification, IMO.