Have you seen the majority of the higher end +smn magic gear? A body that gives +12 to smn heal enhanc etc.... and as for summoning skills it only goes so far for your avatar before the get blocked by the cap SE put on your avatars defence, acc, att etc... I usally sit on about 520'ish smn magic and my avatars still miss when attacking a really high level mob. Not to mention how fast they get killed by said mobs. Avatars have been frozen since lvl 75 for most of their stats.
As for other jobs gear problems they all have several different types of magic to worry about summoner has 1 summoning magic. To me that takes a back burning to gear that gives them an evasion bonus of attack bonus that we can't get from our magic being past cap. My wife's magic is 100lvls lower then mine and she does about 20 less damage then me on most bloodpacts and 2-3 less damage then me on physical attacks. How can 100 lvls of smn magic only account for 2-3 more damage? The system needs a rework so we can have a spot in parties since ours have been stolen from us.