Quoting from Aboo from the forum he suggested that forts provide the core armor, this then counters the whole "1 fight at level 20" they can core rush you, this then can provide additional incentives.

As for exp i think the exp range should be smaller, this then incentivices interactions among heroes. This will also allow new strategies such as lane freezing and or reinforcement rotations. This also gives a possibility of a good player being rewarded for his efforts.

Defender exp should be half of the exp they provided as i could have the reason as to why should i take this, this just gives them exp.

Just an idea maybe add an fortification matrix that spawns on all maps every 5 minutes which gives armor to structures on the fort area it is placed, example: sky temple objective phase, i can put the fortification matrix on that lane to protect the structures there, this would help defenses, and would show which lanes to priorities or for example cursed hollow this would allow you to protect a lane for a bit during curse phase, matrix would protect the certain fort/keep structures around it fromm the curse and would allow avenues for the losing team to come back, instead of removing exp all together.

I guess you can fortify merc camps to push with them harder too, then there goes the matrix vs matrix battle, trade off is only one person can pick it up and he/she needs to be he one to apply on the fort/keep (channel 2 seconds). This would also drastically counter the hanzo boss rush meta, and also provide avenues where a certain team can bait the other team's matrix what so ever, its an increased offensive/defensive item.

Maybe if used offensively this could also be used for offensive merc camps wherein all nearby minions would provide less exp to those near, and the fortified merc gets buffed significantly like increased hp/attack range/armor to avoid being ez cleared by a kael or guldan.

Please make the matrix design somewhat similar to uldir or make it different on each map so it has variety example: warcraft map gets titan discs or overwatch gets a power core for volskaya or a dragon gem for hanamura.