-1 Jack of all trades is good when at work in RL, but in this game being ok at everything and master of nothing = failure more often than not. Your runes are somewhat inconsistent as far as his abilities and needs. Also, changing to the right items you could concentrate more on defense. Try it out and see :)

These are the runes I use personally. If there are better runes people have then I suggest using them. As of right now this set really helps well though it may be a bad set up in your opinion.

And for being mana starved, that's why I go manamune. Once Jarvan gets that and is even slightly fed, the game is over because he has such a high damage output. So no need to switch masteries to a pointless 5 into game make up.

Also, for that early mana regen, maybe consider taking 2 points out of Offensive Mastery and putting them into Strength of Spirit

Alright, so just a few comments/concerns about your rune set up. I don't feel as if you're using your runes to the best of their ability. Might want to consider marks of alacrity rather than glyphs or even just ignore the attack speed all-together depending on which you prefer (as or ad), because of the higher bonus and then move magic resist seals to glyphs, so that you are getting the most out of your runes. As for your seals, I personally don't see very much point in health seals when they are so far below the quints but this is just my opinion. Perhaps another option would be mana per second seals for your early game since you noted that he is very mana starved early game. In my opinion runes are mainly used for early game anyways so after you get your warmogs I don't think this would affect you negatively all that much. Give it a try, you never know =]