Or maybe you are taking the wrong steps.

Soloing Pre-Bind you should take out your weapon at a long distance away and hit with your hardest nuke and just chain nuke. After you get Bind you bind em in place and kill them without being touched even. Whats so hard about that? WHM is definetly harder...lack of firepower AND HP...all we do is do the war of endurance which even i do at higher levels without Hexa Strike..i dont see whats wrong. IF you are lvl BLM for WHM sub then you have Cure too and thats even BETTER.

Every job lvl up after..lvl 6 slows down and thats when soloing is a chore and boring as hell.

In a party theres only very few artilery jobs out there. Only real job that can replace you is a SMN, with possibly another melee, RNG, or RDM. With exception to the RNG maybe, you can do more chunks of dmg than any of the other jobs. Magic Bursts can go over the limit of dmg very easily for you and you are best doing a large ammount of dmg in a short ammount of time. It is very useful to have a BLM when doing large exp chains and managing your MP is important to achieve that chain.