It’s not so much a problem that it is a difficult achievement, the problem is that it locks out progress on other achievements. I’m not a great shot. I’ve switched over to Veteran Drone to learn how to use it to shoot and it is quicker and took a little practice to get used to it. But I’m still a bad shooter.
Imagine if everybody’s achievement progress was blocked by the get 5,000 Direct Hits on the Velociraptor. It’s not a very difficult achievement, but it will take a considerable amount of time to complete. Some will complete it faster than others, but there would be many complaints if your achievement progress was going to be blocked for months because they couldn’t work on and complete other achievements until this one was completed.
I have no problem with achievements being locked behind other achievements as long as those achievements are related. For example; Get 200 Direct Hits on a Common unlocks 200 Direct Hits on a Rare unlocks 200 Direct Hits on an Epic. These are all related and each one is progressively more difficult than the previous. But if you had to Defeat T-Rex 10 Times in PvP to unlock Feed 100 Creatures in Sanctuary those are completely unrelated and your skill to complete a PvP achievement shouldn’t lock out a non-PvP achievement.