Spurs and Chelsea are big 6, and have consistently had larger budgets and spending power than us. It'll be a while before the Big 6 is broken consistently.
And so, yes, I think we're in the next bucket down (and have been for a while, albeit that we've over-achieved). Villa, Newcastle, West Ham, Everton, Leicester will highly likely be the favourites for positions 7th to 11th next season, and all have similar budgets/expectations/etc.
I would state that if we finish:
- above the majority of that group, it will be a good season
- in the middle of that group, it will be a mediocre season
- at the bottom of that group, it will be a bad season
There are reasons to be pessimistic as you've alluded to above, or we could be optimistic that we don't have Frank Lampard or Steven Gerrard as manager, or that we don't have the added stretch of European competition next season (West Ham).