Ok a few holes in this character because it seems like its taking a few things from other characters.
"Attraction": Sounds a lot like Blitzcrank's rocket fist.
"Group heal": That wouldn't fit in with a tank champ's goal in game. Tanks are tanks because they can duke out damage and take it at the same time.
"Attraction Chain": You already have one skill that attracts one enemy to him, what good would dragging all the minions to him do unless they entire aim of the champion is to starve the fellow champ in the lane. Further more, at lower levels, using this skill would cause the agro of all the enemy minions to be focused on the champion, and even low level tank champs are susceptible to DBM (Death by Minion). It would also lead to summoners using this champion to get frustrated as they would be ganked a hell of alot using this skill, again especially at low levels.
"Pressure Boost": Ok, going off the premise that this character uses gravity. I still don't see why causing an increase in pressure in the immediate area would cause a champ to be tp'd back to their base. It would make the champ way to OP if it did. But the idea, even for LoL, is still REALLY unrealistic.Now if it slowed the enemy champs for a duration of time and then exploded for a flat amount of damage plus a percentage of damage delt either to Gravity himself or to the enemy champions which was caused whilst they were in the AoE then i could see it being more realistic. However then thats basically a copy cat of a mix of Swain, Nunu and Fiddlesticks all in one go and would probably be seen as OP as well.
I think if you want a champion to be recognized. Then you should perhaps come up with a back-story to him and also per-maybe-haps put more thought and effort into the abilities he has. And instead of just a brief description of the previously mentioned abilities, give a more concise and detailed description.
THEN! And only then, you MAY get a more positive reception.
These are just my thoughts though, who knows, i may not know anything >.>