More than a year ago I've been actively playing WoW classic by Blizzard. Even wrote this post back then, but never published it, so it's time I guess.

WoW classic provides old fashioned system for your character builds which consists of combination of skills, talents, gear properties and profession bonuses.

Simply speaking player has 3 main tweakable variables to build the character.

Skills which cost money to learn, which influences character development on fresh server. Player could choose to buy a better gear from auction house or learn skills.

Talent tree has just right amount of talents. You can remember them all and think about build idea any time, even when you're not playing.
Talent tree changes are not just adding to your character, but rather morphing char into something different. You can start playing another style by just tweaking details in character's talent tree, additionally combining that with a gear which can have it's own specific properties.

Gear which provides not only stats, but additional bonus effects to your builds. It even might change your talent build and skill rotations almost entirely.
For instance, playing warrior class I found out about this epic sword at level 49. Sword was cheap enough on action house and had a chance to increase character strength for 200 points (which is a huge amount for 50+ levels) for 10 seconds. In combining with crusader enchant, which is outcome of enchanting profession, you can proc +100 more strength for 15 seconds. Each strength point increases Attack Power (AP) Attribute for 2 points for warrior class. Then AP points add to raw DPS (Damage Per Second) attribute.

Pardon me for details, but as I found Destiny sword in game I decided to do a bit of a math on how much better that item would make my character.

I tested attack power bonuses on warrior and it looks like each 20 AP gives me +3-5 points in raw DPS, depending on weapon type, attack speed and overall accumulated Attack Power plus total amount of Attack power with that sword. Skipping the mechanics that I noticed: the faster attack speed the lower coefficient provided from each Attack Power point. That implies each Attack Power point gives +0.2 raw dps. We'll be missing out on attack speed here, but as I see can see it does not get affected by raw Attack Power increase.

Out of this data we can make a conclusion that 1 AP provides +0.2 bonus in dps.
At best case we can have +300 strength proc.
Strength points = STR,
Attack Power points per 1 STR = APR,
Coefficient for raw DPS from each AP point = K,

DPS increase = STR * APR * K

As simple as it formula sounds, Destiny sword occasionally increasing one of DPS multipliers on the character by 200 or 300 STR. It means:

DPS increase (worst case proc without crusader) = 200 * 2 * 0.2 = 80 raw dps
DPS increase (best case proc with crusader) = 300 * 2 * 0.2 = 120 raw dps

Huge numbers, considering that at these levels warrior could have 70-90 base dps provided by other gear stats approximately.

I love such mechanics in character building. It allows player to discover something and then get that x2 raw power during procs I was able to achieve in that case. It brings amazing feelings. Eventually I transformed my gameplay from being tank in dungeons to being tank + top DPS in dungeons. It speeded up the whole process and added fun to tanking mechanics by just keeping aggro when overdpsing other players with focused DPS roles.

I personally think good game design always consists of bunch of balanced choices player needs to make to achieve that peek of interest in the game. Vanilla WoW does it right.