Most profitable professions are considered to be Herbalism and Enchanting in pair. You can have Enchanting only for Disenchanting skill, it will bring decent gold. Consider the fact of disenchanting all soulbound armor, not just selling them to a vendor, but I do not recommend to disenchant any kind of weapons, it is more profitable to sell it to a merchant if it is a soulbound item, or sell it on auction house if it is BoE (bind on equip).
For some weird reason Warlock used to be underrepresented in vanilla WoW. However, the least popular doesn’t mean that they were bad. Warlocks had amazing damage and some truly unique utility abilities allowing them to summon players or create Healthstones for the whole group. Similarly to Hunters, Warlocks were amazing for solo players with the ability to summon various demons to help them.
The primary goal of Conflict and Strife is to provide an interesting choice in PvP by allowing access to an extra PvP Talent. It’s not necessarily going to be a strong option for PvE. The acquisition of this Essence is via PvP, and is totally optional for PvE-focused players. While there may be interesting PvE uses for some of the choices, it is not expected to be a strong competitor on usual PvE criteria (like total throughput) on every spec.
Most people who have spent years playing massively multiplayer online games will tell you that there's something special about the first one you played, too—and WoW was the first for many people. You can become so swept up in the uniqueness of your first experience that you overlook many flaws. It's likely many look at WoW Classic with rose-colored glasses, just as many simply forgot which features were added when. And some of today's WoW players may be too young to have even played vanilla WoW as it once was.