Phantom Assassin + Sven

Why this works

Trying to split the map's farm between Phantom Assassin and Sven often creates a resource problem. Both heroes are position one carries at heart, needing significant gold to hit their power spikes. Sven, in particular, vacuums up jungle and lane creeps incredibly fast with Great Cleave, which can easily leave PA behind on item progression. They don't offer much to enable each other, either. A single stun from Sven isn't the lockdown PA needs to secure kills, and his Warcry armor doesn't do much for a hero who relies on Blur for survival.

This dynamic typically leads to a weak mid-game where the team is waiting for two heroes to come online. An opponent can exploit this window by grouping up and taking objectives. Because both Sven and Phantom Assassin deal almost exclusively physical damage, the enemy team can also itemize against them efficiently with armor or disarms. One of the two cores is usually forced to play from a deficit or in an uncomfortable, sacrificial role, which undermines the reason you would pick them in the first place and makes the overall game plan feel disjointed.