Now to the constructive part of the post, I'll go in order of how I stated them.
3 Lifeblooms (The HoT part of the heal) is outhealed by a Healing Stream Totem that a Shaman can passively keep down. I don't know personally myself but I've heard that lifebloom heals for roughly an extra 500ish since Wrath, even though we have had our health increased by 5 or 6 times.
Our survivability isn't good, if we get swapped to in arenas we're done, of course we have partners for some support but I can survive much better on my Vicious geared Paladin than on my almost full ruthless geared Resto Druid. We have Barkskin but 20% is useless, we have Tree Form but honestly that just makes us die faster.
Onto Tree Form, as I stated above, makes us die faster if we're being focused. When we're in Tree Form we're stuck in Tree Form. We have 2 choices, we can shape out of tree form and waste our major 3 minute healing cooldown, or we can sit in Tree Form and tank all the damage we are taking but that either just ends up us dying or running out of mana from spamming Regrowth.
Nature's Swiftness for Druids is a 3 minute CD, Shamans is 2 minutes. To be honest this makes no sense to me, the only difference is ours give 50% bonus to our next nature spell. I know all the classes are meant to be different, but considering they have the same name, same effect, I don't know why Druids get the short end of the stick.
Some suggestions I've read from other threads / thought of to help Resto Druids in arena without effecting PvE (I know Resto Druid are good in PvE so that's why I'm avoiding anything that might make Resto too overpowered for PvE).
The most common suggestion I've heard of, make Tree of Life a buff, and not just a shapeshift. You should be able to pop Tree of Life and go into Travel Form and back to Tree if you need to heal. What it is now to me is like a Paladin popping wings and using Hand of Freedom and Hand of Freedom removing the Wings. I know they're completely different, but you get the idea.
Give Druids an Aura Mastery / Inner Focus type of thing. There are certain points (75% of the time) where all our hots on a target isn't enough to heal them through all the damage they may be taking, there's some point where we need to some sort of protection to get our casts off, you could say Tree Form helps with that, but every other healers has their healing cd's and also a (excluding Shaman / Holy Priest but who rolls Holy Priest in arena) aura mastery type buff.
Redesign Perseverance (2nd tier talent in the Resto Tree), instead of a 6% spell reduction (when 3/3) give it a 3/6/10% damage reduction to everything. 3 Talent points for just 6% spell reduction right now is almost worthless especially with all the damge spell casters do, but that's a different thread; or even keep it 2/4/6% damage reduction but for all damage and not just spell.
Make our 4/4 peice set for PvP allow Lifebloom to be on 2 targest, I can't even count how many times I've had 3 lifeblooms on 1 target, then the enemy switches extremely fast so I need to start stacking lifeblooms on the new focus target before my lifebloom even gets to bloom on the 1st target (which ends up leaving them not at full health).
Increase Cyclone Range from 20 (25 with PvP Gloves) to a 30 (35 with PvP Gloves, or change the Glove effect) yd range. We're the only one with our spammable CC at such a small range. Granted it's undispellable, it's just too hard to get off when we need to get so close to our enemies making ourselves very vulnerable.
Put something in like Outbreak for Death Knights, but for Druids to apply all hots (excluding Regrowth and Wild Growth) to the target, this would effect PvE slightly but I think if it was on a decent cooldown (Something like 1 minute, maybe 45 seconds) it wouldn't effect it to bad. Then again I don't play Resto in PvE so I can't really say much.
This last one isn't as game-breaking as the other suggestions might be, but give us some sort of pushback immunity to certain spells (Cyclone for sure, possibly Roots & Hibernate?) someone in our talent tree.
Anyways, some of these might be a little overpowered, but in the current state we're in we need a buff. Just my thoughts, sorry for the wall of text. >_<