Old thread and all but in case anyone actually reads this part of the forums here's what I've come across. I've played doomcryer main for about 6 months with pom as dualclass. I've now switched my main class to sword singer. Doomcrier was nice when it had the combined harmony. As things are right now it's just a very generic iss. Like a dominator but their bison skill is only limited to party members, unlike vop.
With that being said, you shouldn't have trouble keeping bison up at all; nor do you need it to be +20 to do so. Prestige pack, +8 light armor set, green or red ari homunculus, exalted sayha talisman, greater aquamarine, dualclass certification skill for skill cooldown and ability points setup are only some of the options you have for getting the skill cd much much lower. Also, enchanting bison for time increases its duration for 15(?) seconds, unlike pom that gets an 1 second per enchantment increase in its duration.
Either way, what it all comes down to is that parties will show a preference to basically any iss other than doomcriers and/or dominators. You can have a dominator giving you the exact same buff as bison outside of party while also having a sword muse/blade dancer giving you their buff in the party.