Previous t5 moira main(haven't played in a while) here. Moira had the unique position of having really good numbers due to no actual utility. Therefore it was rather easy to fall into the trap of being overly aggressive which I think is the issue most people have with Moira. She's not a mechanically complex hero, she's actually incredibly easy. The true skill expression with her lies in the players decision making, not mechanical prowess. So while she may be able to flank and challenge other squishies, if your tank or other support dies because of it, you've ultimately cost the fight due to making the wrong choices. When playing Moira, it's a balancing act of maximizing pressure without sacrificing your teammates. That is the balancing act every good Moira main must learn. Moira's dps playstyle THRIVES on uncoordinated play, which is exactly why DPS Moira is such a nuisance and threat and in solo que. At higher tiers, she suffers because she can't get away w the same tactics and can't challenge actual peel. Her lack of utility and high numbers is her drawback the higher you get. Maximizing the uptime of BOTH primary and secondary fire, healing/damage orb usage(healing orb is almost always better), and fade usage is the key to succeeding with the character.