To start with, I did a small amount of research using the Google, and discovered something very, very important:

Players value their knight and want something that ties into the Spiral Knights.

To discover this, I typed the following into google, as I had glanced over the suggestions I was looking for in the past:

spiral knights iphone app suggestions site:forums.spiralknights.com

And I got suggestions such as, but not limited to, these:

http://forums.spiralknights.com/en/node/45128
http://forums.spiralknights.com/en/node/81306
http://forums.spiralknights.com/en/node/41215

The most notable features in these are the following:

Another thing players want is the entire game ported onto the mobile market, but this idea was typically countered by things like "You have no idea what you're talking about.." which tells me that first, players are understanding that it's implausible, and second that they do want combat features etc.

But more importantly, these things tie into the main game, which Rise of Knights does not... so how do you make Rise of Knights succeed?

Cross compatibility!

Which is a genius solution for a number of reasons-

1. It's something that hasn't really been accomplished before, but that holds great appeal. This would separate RoK from similar titles as well as innovate a much needed area.

2. It starts with a set of players. If I can earn something in main Spiral Knights just by playing a phone game, you know exactly what I'm going to be playing while I'm waiting for the bus.

3. It grows the current player base. If I start playing Rise of Knights without having heard of Spiral Knights, all of the sudden I'm going to want to play Spiral Knights- especially if I get a head start via my Rise of Knights play.

But how???

Step one would be to link player accounts between RoK and SK and allow for some carry over from one to the other. A good and very necessary example of this would be your current setup on your knight, which needs to be placed into RoK, and begs the question as to what happens when the gear leveling clashes? I'd personally say that your gear on your knight is separate from your main gear on RoK, and can only be leveled on the main client. Why should your knight from SK go into RoK? Because that sort of thing would make progressing on Spiral Knights highly beneficial to your Rise of Knights strategy, and would be highly awesome, which is really all that matters.

It would then be necessary to make sure SK and RoK are cannon with one another, even if a bit loosely. This allows for lore to be transferable between the two games, and for gaining things from your phone to make sense. The plot to rise of knights could be described as your knight getting a chance to lead others as opposed to going solo, or it could be some sort of dream state that your knight goes into.

Following these things, access to auctions and a common source of energy. Jewels become energy, and the auction house on Spiral Knights gets upgraded to factor in the new game, while making an appearance on your phone. This allows for already wealthy players to sink money into (and become addicted to) the new phone game, and for wealthy phone game players to get a head start on the established Spiral Knights. It also makes the energy market feature make drastically more sense.

Finally, Rise of Knights needs to provide the player with something nice on Spiral Knights. I would personally suggest making new status variants for the battle sprites and a handful of weapons that require materials or recipes from the mobile version of the game, as well as possibly just straight up crowns, but in limited quantities. A new token currency could also be used to facilitate all of this- think of a Rise of Knights Token, which would be traded for the materials needed for a select few gear items.