I'll start by saying there has always been newish people who don't understand the game, and have complained about all races being too weak, including dwarves. I've been of the opinion that they were very strong until these last few patches, and the balance of Dwarves is precarious due to the permanent death mechanic of so many of their troops. A small change can turn "great" into "worthless".
In the current game, miners are not viable at lvl 13. They route, they are slow, their feature stun mechanic doesn't make a meaningful difference. They can't be res'd like swordsmen, they don't have self-heals, large bonus and elemental resistance like scorpions. Few people argue that these are an actual option for high end duels or garrison breaching, so let's just get that out of the way.
After a few consecutive patches making dwarf stronger, all the most recent changes in the game since have been net-buffs to humans, and some part lich. They include the following:
Dec 21 -Defensive mode for Avalon and Elena. Two critical human heroes who's continued survival benefits humans more than anyone else.
- Virion can no longer die before using Light's Safeguard. This added immensely to the consistency of swordsmen revives, and his humanoid buffs.
Particularly against deadeye crits.
Dec 6 -Greatly reduced the healing time of injured Gold-level troops. Reduced healing time for all troops at level 3 and above. A big change that effects everyone to a big degree, but Dwarves the least.
Nov 8 - Greatly increased the health and attack of Archers, Longbowmen, and Feathershots. Increased the flight speed of arrows.
-Greatly increased the health and amount healed by Priestesses, Abbesses, and Saints. Greatly increased the healing range.
- Greatly increased the health and attack of Acolytes, Occultists, and Warlocks. Increased the flight speed of basic magical attacks. Greatly increased the ranged attack range. Improved garrison troop attack logic such that multiple targets will be attacked at once.
-Greatly increased the health of Mummies, Conjurers, and Necrolytes. Increased the flight speed of basic magical attacks. Greatly increased the ranged attack range. Reduced the Resurrect time interval. Greatly reduced the training cost.
This patch was devestating for dwarves. You will note in Lilith's patch history, they rarely "greatly" increase anything. This essentially added a level to archers in terms of damage.
Oct 24 - Centurion**: Increased attack and HP; Slower Morale decrease; receive 30% less damage from Large Units.
- a "slight" increase in HP/attack to mechs in this same patch. Something, but totally irrelevant in the face of the later archer buff.
Previous to this, the introduction of Yip with 30% archer damage boost (also reduces dmg from enemy archers, but obviously a more human hero for the simultaneous buff) and lich having their garrison permanent death units revive.
So where we are left, I have a collection of half a dozen replays of full gold dwarf armies being blown away with disproportionate costs. Humans can throw silver armies at gold and eventually break through, and lose less than the cost of a single gold mech squad dying with 90% injury rating. Rocketeers are still strong, but totally ineffective against scorpions, but with no viable front-line for dwarves... When a dwarves garrison is attacked, he loses his career's worth of accumulated units to permanent death. Lvl 13 units who run out of ammo on the wall are still a joke compared to the "greatly" buffed archers.
Some of these changes were necessary and good ones, but it nonetheless has the effect of reducing the power of Dwarves.
edit** The map also works against dwarf. I understand there being less tundra due to the race distribution, but it is also remote and inaccessible to most factions (in the age of migration and sever merges, your hand is forced). So there often isn't even defensive recourse for dwarves, let alone good targets where they can utilize the offensive bonus.
Dwarf still has a place, but it's neither an autonomous or irreplaceable one. Anyone can kill walls fairly quickly with siege, and fielding 2k mithril worth of (superior) dwarf siege which can be killed to random targeting is rarely a good idea.
Even Dwarf whales fielding 16 heroes winning duels vs humans (never lich), are still losing immensely more resources than they kill with each battle, on friendly or enemy territory. This trend of patches is concerning, and you will witness a exodus when the race change patch is introduced, unless something changes.