The Savage
Innate: Envenomed Javelins
Each attack applies Venom, which deals damage over time and slows the enemy’s movement speed, this stacks up to 10 times.
Skill 1: Harpoon
Throws a harpoon that pulls you towards the first target it contacts. Applies a stack of Venom. May attach to allies without damaging them.
Skill 2: Call Familiars
Summons a quillboar, which applies stacks of Venom with each attack, and an eagle, which has True Sight.
Skill 3: Miasma
Throws a vile of goo at the target location, laying down a pool of miasma. This deals damage and applies a stack of Venom to enemies within the area of effect. Damage increases every second that the target stays in the area of effect.
Ultimate: Bad Blood
Saps life from nearby enemies with a multiplier based on how many stacks of Venom they have on them.
Mananers 
Consider TOB:
We have three phases. In early game, players are spread out (usually in a particular fashion), primarily attempting to gain gold and XP and deny their opponents’ the same. Pushing is impossible because towers are too strong, and kills are rare because of the spread, travel time, and skill selections usually aimed at creeping. Mid-game shifts to the flanks, with each side pressuring/defending the other’s expo. Kills are typically scored here, with one side going ahead in lumber, and perhaps scoring some progress. Items are rarely used due to their expense. The middle of the map is too open and too long for pushing, which is why play concentrates on the flanks. Items are out in full force, but generally are consumables or speed buffs. Late game, we see towers appearing because heroes alone can’t push effectively thanks to enemies having closer fountains and respawn, not because of towers or creeps. Particular items may make an appearance as part of a long term strategy. Pushes are supported by hirelings and are made full-force. The middle becomes important once more, and generally there’s a single united front instead of each lane having its own shifting front thanks to how players move. Eventually main is slowly overcome as lanes fall.
You’ll note that the particular heroes used generally have little impact on the grand structure of a game. It comes about as a result of how peripherals like items, creeps, towers, lane structure, and hirelings work. That’s what you need to focus on.
I suggest the following:
At one given base or at main (or possibly at each base, although that’s a lot of buildings), each side’s creeps build a Lumber Mill. The Mill takes several minutes to finish. When the structure completes, the towers receive an upgrade. A Mine, following similar parameters, is also constructed at the same time and buffs a base’s creeps. Etc.
This process repeats for a couple tiers. So after the LM, we have a Foundry built, that makes towers even better. After the Mine, perhaps a Smithy or something to buff the creeps to tier 2. Then we have an Engineer’s College, and a Military Academy. Or something.
Players can help out with this somehow. Either they can repair-build the structures at the cost of their own gold and micromanaging peasants, or they can purchase upgrades of their own for creeps (perhaps only at a specific base), or both. Or persistent spawns or one-time spawns. Whatever. We shouldn’t give too many options though—that’s dumb for a lot of reasons.
Because creeps and towers scale, they never become irrelevant. This allows us to start them weak enough to allow for early-game pushes, meaning no phase of the game is a meaningless grind. Oh, and the addition of these buildings gives players additional targets to gun for.
Because the creeps build them, players are free to spend their gold on other things. They can choose to help out their side, or to save for items, or whatever. This allows us to put in place a robust and interesting item system that isn’t completely outclassed by faction-wide upgrades.
Other things to consider are spawners, laning structure, and forcing an endgame. Maybe I’ll write about those later.
Oh, also the use of lumber, or if it’s even in the game.
Actually having lumber be tied to the “force the endgame” thing isn’t a bad idea at all. Just make every lumber-based purchase offensive in nature, or else have the defensive ones outclassed (either immediately or gradually) but the offensive options.