For both beam morphs have the damage per cast be roughly the same but they ramp up in damage over the duration starting out doing roughly half ending up dealing 2x damage ticks at the end making it more important to channel the beam fully to get full damage out of the skill, so skillful players that can avoid crowd control or know when they are likely to get CC'ed can plan around it and for those that use shield beam there is no longer a minimal loss in damage loosing the last few seconds of ramping damage for the insane safety that skill provides.

This would actually make game knowledge useful to fully utilize arcanist and make a significant difference of an absolutely cracked arcanist vs some pug that just presses beam (in content at least as trial dummy can only show so much and damage numbers would likely be similar)