I personally think you're being restrictive with the meaning of important goal.
Shouldn't we measure the importance of a goal by how crucial it was when it was scored, as opposed to how important it was in hindsight, which maybe ought to be classed as the decisive goal.
For example against QPR both Zabaleta's and Dzeko's goals were hugely important at the time of scoring. Not decisive like Aguero's (which in truth was also important), but they were both still important.
I've made a list of goals which I think were important at the time of scoring, and I class such goals as goals that allowed us to bring the deficit to one, equalise, take the lead, or go two goals clear:
Swansea (H): Dzeko, Aguero
Bolton (A): Silva, Barry, Dzeko
Tottenham (A): Dzeko x2
Wigan (H): Aguero x2
Fulham (A): Aguero x2
Everton (H): Balotelli, Milner
Blackburn (A): Johnson, Balotelli
Villa (H): Balotelli, Johnson
Them (A): Balotelli x2
Wolves (H): Dzeko, Kolarov, Johnson
QPR (A): Dzeko, Silva, Touré
Newcastle (H): Balotelli, Richards
Liverpool (A): Kompany
Norwich (H): Aguero, Nasri
Chelsea (A): Balotelli
Arsenal (H): Silva
Stoke (H): Aguero, Johnson
Liverpool (H): Aguero, Touré
Wigan (A): Dzeko
Tottenham (H): Nasri, Lescott, Balotelli
Fulham (H): Aguero
Villa (A): Lescott
Blackburn (H): Balotelli, Aguero
Bolton (H): Balotelli (Sorry Clichy)
Chelsea(H): Aguero, Nasri
Stoke (A): Touré
Sunderland (H): Balotelli x2, Kolarov
West Brom (H): Aguero x2
Norwich (A): Tevez x2, Aguero
Wolves (A): Aguero, Nasri
Them (H): Kompany
Newcastle (A): Touré x2
QPR (H): Zabaleta, Dzeko, Aguero
A list of important goals scored compared with total scored:
Aguero 16/23 70%
Dzeko 8/14 57%
Balotelli 12/13 92%
Touré 5/6 83%
Silva 3/6 50%
Johnson 4/6 67%
Nasri 4/5 80%
Tevez 2/4 50%
Kolarov 2/2 100%
Kompany 2/3 67%
Lescott 2/2 100%
Milner 1/3 33%
Barry 1/1 100%
Richards 1/1 100%
Zabaleta 1/1 100%
Ok, long and probably boring. But if there's anything to take away from this then:
1) Balotelli, Aguero and Touré all know how to step up when it matters.
2) We have a lot of players who have scored vital goals, which suggests a strong mentality in the group.
Sure, some goals in the list were more important than others. But devising a way of measuring the exact importance is difficult.
Anyway, long story short, Almost all our goals were important. We should appreciate that.
ps. Apologies if I made an error here or there.