Uriel is a highly specialized and very niche specific role. Uriel is tanky and offers massive ground control and his attacks aren't affected by armor offering massive damage to elites and heroes alike. Donatello and the reaprs are able to climbs cliffs and snipe poorly defended tanks or tumors. Both heroes have a relatively short range and a low amount of damage to begin attack for attack, but their true strength comes in from ground control and their quick movespeed making them uncatchable except for in the event the Devil decides to chase after the reapers or a fungal catches them.
Their goliaths offer huge amounts of anti-air damage as well compensating for the heroes lack of anti-air. They deal large amounts of damage to ground as well, but their slow attack speed is not impressive and not best suited for large amounts of low hp units. This is where Uriel's role becomes apparent as ground control.