Explosive Shot (E) Much Ado About Nothing:
Ok, after trying every ability growth and throwing conventional wisdom to the wind I have the following conclusions.
If you want to maximize Tristana damage across a 5 second window with all your abilities up do the following:
Buy abilities in this order:
Explosive Shot, Rocket Jump (W), Rapid Fire (Q), Rapid Fire, Rapid Fire, Buster Shot(R), Rapid Fire, Rapid Fire
Yes, Moba-Fire is not good. Moba-Fire says buy Explosive Shot until you max it. This is the worst decision for your damage.
But WAIT you say. I don't have a BFSword yet you say. Shouldn't I go into W and E which are traditionally non-item dependent abilities?
Well, first off, Explosive Shot requires AAs now so not much different from Rapid Firing. Infact, other than AOE damage, Explosive Shot is an inferior Auto Attack (AA) steroid to Rapid Fire in almost every way.
Secondly, Rapid Fire helps you complete the AAs you need to maximize Explosive Shot. Rapid Fire AAs increase your damage based on your total AD and to add salt on the wound multiply based on your crit capabilities (duh auto attacks are auto attacks hue hue).
Thirdly, Explosive Shot's damage growth between levels 1 and 5 is none existent (10 dmg total x2) outside of bonus-AD multiplier. Rapid fire, on the other hand, multiplies the entire Total AD including the base AD not just the bonus-AD.
Fourthly, even if you have 2 BFSwords, Rapid Fire is superior damage output over a 5 second window. At max rank it provides approximately 3.5 extra AAs in 5 seconds. At max rank Explosive shot only provides 2.2 bonus-AD + 200 flat. That comparison is not even close, but incase you don't trust me we have math. Explosive shot is the icing for the cake when you are done making the cake. It's good to have, but its not going to fill your guests up with damage.
Fifth, Rapid Fire takes towers down too. Remember when I said Explosive Shot is an inferior AA steroid? This is me reiterating for clarity.
Lets Math:
Level 2-5 Rapid Fire levels each increase your damage by AD x 0.67 x 0.2/sec x 5sec x crit-stuff = .67 AD x crit-stuff. This is an increase of 2 auto attacks or more by reaching level 5. With a Blood Thirster (say 160 AD total) That's an extra ~100 physical damage per level of Q beyond 1.
Level 2-5 Explosive Shot levels each increase your damage by Bonus-AD x .30 + 20. Lets just say it's not good growth friends. It reduces your in fight options and at the benefit of approximately 1 auto attack by reaching level 5. With a Blood Thirster (say 160 AD total) That's an extra ~44 damage per level of E beyond 2.
Don't get me wrong:
Level 1 Explosive Shot and Rocket Jump are good. They are very good. You get almost half the damage value of level 5 with 1 level in each of these abilities. Still get level 1 Explosive Shot and Rocket Jump right away!
But Rapid Fire is on a 20sec cool down! Yeah, I didn't say it would be a completely happy trade to level Rapid Fire first. It's mana free and keeps your E cost down a bit. Don't punch a gift horse in the mouth may apply here?
In conclusion, yes Explosive Shot can do more damage than it did before the rework, but it requires a lot of bonus AD to do it. Without bonus AD it does less damage even at 4 stacks than the old magic damage variety at level 5. If you have a lot of bonus AD you want to have Rapid Fire first and most because it's that good, it's not gated and it doesn't reduce your in combat decisions down to your initial target if you want results.
I just had a game where I went 15/5/5 with these ability purchases and my support said I was poo expletive. Did I honor him, you bet I did, we kicked butt and I have barely won a game since I started playing Tristana again. I am rusty. Was he wrong about my build and decisions regarding Explosive Shot, I think so. Am I a bad ADC? Not in some small corner of a relative universe.
Hope this was helpful. Lets get some of those Moba Fire sites updated. - Bast
3-17-2015 (I need to date this because abilities change which affects the validity of the analysis)