Can we just enjoy the championship for a few seasons ?

If we don't strengthen I think we will be in the bottom half. A poor run, or a load of injuries could see us sucked into the relegation dogfight.
If Coventry are the benchmark (finished 12th, 64 points) there is a lot of work to be done to get to that level. The squad as it is now would have to play out of their skins every week to get us top half/pushing top 6 - bit like a lower league cup team beating a PL team. It's do-able on a one off, but unlikely over the season.

Having said that, 4 or 5 key additions and we have the potential to be comfortably mid table, but strength in depth is going to be the key - our bench at the weekend was minging