I have had this problem from the very beginning, being a first generation player I can attest to the difficulty of fighting ranged units. Musketeers and Witchdoctors are way to strong against close combat units. I've learned how to deal with Musketeers a bit more but it still doesn't change the fact that 99% of the time a ranged unit will not miss and it's even worse for the 100% accuracy of a skill. Up until Aquila I was able to solo the game for the most part until the Witchdoctors of Aquila made it virtually impossible for me to do so. For the first time I had to actually summon henchman to assist me against them and even then I've won more times by the skin of my teeth then I care for. The witchdoctors not only have the widest attack span but they're witch hunter skill stops any hope of an effective attack. Plus, their attack strength is utterly ridiculous.

I am a swashbuckler with a very high dodge rate and yet I never dodge a witchdoctors spell or musketeers bullet and on the off chance I do Jobas Ruse and Quick Adjust remedies that. Fighting a hoard of Satyrs is one of my most frustrating moments ever.

I implore you. Please do something about the severity of ranged units.

Dont worry, think about all the max level swashbucklers you see in pvp! They've all done that, and it means you can too. If you haven't noticed, accuracy is terrible, and if you dodge them and their jobu's ruse activates, then they wont attack the whole group like they would if successful on their first attack, and you're likely to dodge again.
Secondly, you can get alot of resistance (40ish at level 60) with a robe from the bazaar.
Thirdly, and while this isn't as important, have old scratch and reset his epics so he has witch hunter 2. This is like a first strike or quick draw but for witchdoctors, and it also reduces their damage (around 30-50% roughly) so it's extremely good, especially as you're getting potential mojo echos. I'd go with Witch hunter 2 and mojo echo, not improved mojo blast 2 because he's going to trigger a whole group of witch hunters, then his attack will be so miniscule and his health so low it wont make a difference.

Check out this guide. http://pirate.mercenaries101.com/counter-companions/ If jack doesn't let me post the link to mercenaries for charter just go to counter companions mercenaries for charter.

Have fun slaying death saytrs!