Is Spike an unnecesary character or one that is badly used?

Long shot (and personal opinion)

Spike. The loyal assistant of Twilight Sparkle long before she even became a resident of Ponyville. This little guy has known Twilight for all of his life and it could be argued that he acts as a moral compass for our Princess of Friendship, even though sometimes he screw things up. But it is really his fault? Or perhaps his character is badly used?

Across the seasons, he is showed to be a bouncing personality to the main cast, even to the point he exceeds in some key elements, For example:

1.-He can be the voice of reason for Twilight´s burst of madness (lesson zero for example) and also be one of her greatest pain in the flank or comedy relief. (secret of my excess, Princess Spike).
2.-He can be Pinkie Pie´s sidekick in good events (Fall Weather Friends) or be creeped by her (Party of one)
3.-He is Rarity´s greatest admirer but knows when to stop and be assertive with her (Inspiration Manifestation)
4.-He can be protective of Fluttershy but also give her courage (Scare Master)
5.-He can do practical jokes with Rainbow Dash (It´s about time)
6.-And he can be for short but meaningful moments a empathic character with Applejac when someone is doing more that he/she can do (Winter Wrap-Up)

You could argue that other characters, and even within the main cast, make the same things as him. But not at the same intensity. By heart he is a support character for all of them. He reflects the best and worse of any of the main 6, allowing them to grow with him as the series goes. He is written to the point were he has no real aspirations for himself. And there lies the problem.

When Spike takes the lead in a episode, most of the time ends with lackluster results. He tends to be annoying and sometimes ends in other characters fixing problems that he caused in the first place, in Princess Spike he abuses of his new authority to the point of nearly ruining the event for example. The only episode that I can recall right now where he shined as the lead character is Dragon Quest. Sometimes his efforts tend to prove fruitless when the other characters do the work.

Does that mean he is unnecesary now that the main six have stronger bonds? No! Spike is neccesary for the show, especially in Twilight´s life. But what I honestly believe he needs right now is a personal drive beyond of being Twilight´s assistant and friend. And if the writters have in heart that being her assistant is more than enough, then they need at least one episode where his loyalties with her are put to the limit. They have argued with petty things like jelously and such. But have they truly being separated because of bitter emotions or momentary hate? Does Spike really has a self or he only follows what he has in life? Dragon Quest ended in accepting himself as a part of the pony family, but it didn´t gave him a goal to pursue.

I hope he can be expanded more in the next season. Kudos for reading my post and thanks.