Just to start off: this is not a troll attempt, nor is it (in my view) much of an exaggeration.
Warning: wall of text ahead.
With HoT coming and the proposed changes to traits, skills and gear, GW2 as it is today will disappear. Rather than simply introducing new content, the devs have chosen to rework pretty much every aspect of build design.
Traits
Traits have been changed in several ways: they no longer give attributes, you are now forced to take major traits in their designated tiers, and the traits themselves have been culled, merged and re-arranged.
Let’s take a look at how many you get per ‘specialization’ (read: trait line): you now get 9, where before you had 13. Now there were MANY useless or exceedingly niche traits that could definitely be safely removed without much fuss, so this reduction in total number is likely a good thing. However, keep in mind they have also said they are introducing new traits as well. So not only are you dropping 2 traits on each of the adept and master tiers right off the hop, but some other current traits may have been replaced with new ones.
New traits are a good thing, but considering the list of sweeping changes, they will also be a lot of new information. Devs have explicitly stated they intend to keep many of the current builds viable, but I can’t help but think this is lip-service — not because they aren’t keeping key-traits, but rather the trait changes in conjunction with the OTHER changes they are implementing will almost certainly uproot currently established meta-builds (which I, personally, like).
Also, as a side note: there were several builds that went into 4 lines or even all five. These builds are now impossible to use.
Skills
Some of those removed or replaced traits will have their effects tacked onto existing skills. While it was vague whether this meant solely utility skills or whether this included some select weapon skills and such, this is another big change. Skills currently held to be strong may have some competition (which is good) from skills currently considered niche or underpowered. Additionally, the ‘elite specialization’ (which I personally think is a poor term as it denotes a higher level or efficacy than the ‘base/core’ specializations but that’s a different topic) will give you access to 6 new skills — that’s 54 entirely new skills to learn across all classes, in addition to re-learning however many of the current skills that got a facelift.
Gear
With moving attributes off of your trait lines (which I approve of, at least in theory — traits should be important by themselves) you will almost certainly need to make new gear to optimize your build. Even if you are close, the limit of having 3 different stats per piece of armor will likely mean you numbers will be a little wonky — maybe only a little, maybe a lot depending on your current build. Now exotics are easy to get, but Ascended gear is more expensive be a large margin, and there isnt’ an alternative way to get it (currently).
Conclusion
Combining all these factors, there is a LOT of new information to learn. In a way its a great thing, it will breathe new life into a stagnant meta — but at the same time it is pretty brutal to do it all at once. Perhaps its cleaner and you garner less outrage overall (rather than adding a world-changing tweek every 6 months or so), but it remains a near total overhaul of current systems.
Reducing/changing the major traits, forcing a trait to stay in its tier, an unknown number of drastically altered core skills, and 54 NEW skills is tonnes of change. You will be pretty much re-learning how to play gw2. Are you ready?