I am not going to tell you how to improve your way of playing the game, HOWEVER, I will just tell you how I play the game after many decades and using crap to average and the odd above average gear. Hopefully the info helps you choose what is best for you.
Feeder Class: I prefer Guardian, however, in your case I would choose Barbarian over a Fighter.
Reasoning or my perspective(s);
#1: Retribution Ability charges up with "Hits Taken", so when you encounter 2 or 3 monster wave, it can charge up faster than using Power-Strike that charges up with "Successful Hit Chance / or Damage Dealt" (forgot the wording, basically each successful hit, you get a % chance that the ability will charge up.) Any "0" damage dealt or received based on those abilities will NOT have a % chance to charge up.
#2: Using Retribution or Salvation abilities require using Armor with less Enhanced Effect % for better Defense, so I prefer using +Stat armor.
#3: I like to Heal, so I use Salvation, I also have a specific Maximum Stat # for Vitality & Intelligence for EVERY Class. 100 min/max Vitality (adding hard points), 30 minimum Intelligence (this is for mana pool, and a minimum of 100% EE for my heal charms, especially at higher levels). Note: I will add 25 points to Intelligence with my Barbarian after I reached 100 Vitality, any other stat points go towards my weapon stats.
Now you must be wondering WTF is up with this guy and play-style? Well I use a numbers game in a sense, I only solo play as well. Let us do the numbers a little:
You start off with 10 Starting Stat points @ level 1, for myself, I would add it all to Vitality.
Guardian:
... Str: 30 (@ level 37+ add points if using Club, Longsword, Warhammer & Battle Axe)
... Dex: 10 (@ level 37+ add points if using Spear, Polearm or Battle Axe)
... Int: 55 (no need to add points since above 30 minimum)
... Vit: 55 / +10 = 65 (by level 36 [excl Objectives] = 100 min)
Barbarian:
... Str: 60 (@ level 56+ add points if using Sword, Club, Axe, Warhammer or Battle Axes)
... Dex:25 (@ level 56+ add points if using Polearm)
... Int: 05 (@ level 32 [excl Objectives] I add 25 points to min 30 = by level 56)
... Vit: 60 / +10 = 70 (by level 31 [excl Objectives] = 100 min)
Fighter:
... Str: 50 (@ level 61+ add points if using Sword, Club, Axe or Long-Sword)
... Dex:40 (@ level 61+ add points if using Spear or Polearm)
... Int: 10 (@ level 42 [excl Objectives] I add 20 points to min 30 = by level 61)
... Vit: 50 / +10 = 60 (by level 41 [excl Objectives] = 100 min)
Now, at level 55, each of these classes have the same amount of Hit Points & Physical Defense with 100 Base Vitality all the way to Master Quest.
Now, at level 55, only two classes have a minimum of 30 base Intelligence for Mana Pool and Magical defense. (Fighter needs 5 more levels.) Noted that Guardian benefits with more Mana pool vs Barb, however, Barb benefits more from Strength, a Guardian @ level 55 = +49 Base Strength vs a Barbarian with 60 ... you have to weigh up what you want to achieve for your runs & Speed.
This is one reason why I prefer Barbarian vs Fighter, both of these characters can use the same two Abilities if ignoring Healing. Retribution & Power-Strike. I only like using two (2) abilities, I also prefer to Heal, so one of my abilities is Salvation, and since I only use +Stat armors and NOT Enhanced Effect (EE) armor, I prefer Retribution over Power-Strike... Oh, forgot to mention... I prefer Heavy Weapons, this actually makes a big difference in your build(s).
You have a mind, you know what you want to do and how you play games, so it is up to you, the following is based on why I prefer using Heavy Weapons.
Simply put using weapons & why I like Heavies:
... A White Heavy Weapon deals Double Damage = 100% Enhanced Damage (excluding Stats and Modifiers from items, and only using the base stats of the character class). NOTE: Yes, normal weapons have a 1 second delay action vs a heavy weapon with 1.8 second delay action. You will notice the difference at higher levels playing the game, as for low levels... yup, use normal weapons up to level 15, then test out heavies, or compare in your runs what you prefer to use.
