This was an absolutely amazing game, by far my favourite DS game. I clocked up over 2000 hours on it...:x. I played in clans (and am still in a popular gaming group which used to play Metroid Prime Hunters as a rec).
Sylux was basically good because of the Lockjaw. Shock Coil was probably the best method of healing on small maps such as Sanctorus and Combat Hall (but Sylux sucks at Combat Hall, anyway). Lockjaw was useful for running on Alinos Perch.
I agree, when MP:H first came out it was an Imp fest. But in all honesty as it went on players such as eXc355umTEC (I too am in TEC), and Perfect_Edge, found more and more cool weapons which were hugely viable (namely the Volt Driver, Magmaul, and Judicator).
The problem with the Imp on WiFi was trying to find player's lag spot...some days you could hit them for a 7-0, and the exact opposite would happen the next day.
Here's an example of the Volt Driver being used to its fullest.
Samus is a great character...Morph Ball does a tonfuck of damage if you time it right. Triskelion isn't hugely superb, but useful. Spire plain sucks. Noxus is cool, especially for Shadow Freezing which was pretty much allowed in matches (unless specifically asked).
In all honesty I love this game, and always will. It's the game that got me into playing WiFi, and which led to me playing other games on WiFi (read: Pokémon). This game is truly amazing!
However, I quit playing about 6 months ago. I played the game hugely, and it was time to pack it in.