Please note that this review is written from bad to good.
In my eyes, the campaign system feels somewhat lacking. There are mechanisms for travelling around the world, having random encounters and various things, but when you first start out, the game does not help you give a motivation for your character to actually do so. There are quite a few aspects where you need to fill in such gaps, giving the character reasons and motivations in order to justify decisions made purely in order to activate the mechanisms - or the other way around, filling in gaps that the system leaves. The latter can be seen with cities, villages and towns. While there are some differences, there is no real incentive to visit a city as most benefits of it over towns are rather marginal or dependent on getting lucky to get an involuntary encounter to begin with.
Mind you, those things can be handled by house-ruling, but even though that is really easy to do, I think it is not the way a product of this price category should be. Especially since the description claims that the engine provides you with a "why" for your adventures, which it does not, most of the time.
Another, personal, failure of the game is based on the information on the homepage of the designer (which is in turn information that is on the back of the book). "Legends aren't born, they're made" is the motto, followed by an explanation that suggests that you may start as an "inexperienced spellcaster" (among other things), and that you are nothing special when you start the game. Then you read the rules and they are designed in a way (and is suggested that you abide by it) that you start as a REP 5 character. REP 5 is defined by the game as "veterans of numerous successful encounters. Knights and Veterans would have a Reputation of 5." That does not really sound like nothing special, does it? An average soldier is REP 4 and someone who has limited combat experience would be 3. And as far as character development goes, REP 7+ is the highest category reserved for incredible creatures. Basically, you start in a position, where you could - if you are really, really lucky - reach the highest standing in the game in 2 fights (admittedly, you have to be very lucky, but it is still quite possible). The promise of development seems to be undermined.
As with the 2 Hour Dungeon Crawl, the price is also rather steep, although not as extreme as with the Dungeon Crawl. However, if you remove the material that is virtually identical with Sword Play rules, which are given away for free, things become dimmer, as we are left with the campaign system, the dungeon crawl system and additional interactions and magic items.
This brings me to the next negative - the dungeon crawl system. Personally, I think it is inferior to the one that comes with the 2 Hour Dungeon Crawl. While the 2 Hour Dungeon Crawl system creates potential encounters sometimes not in your current location but nearby and then has them chase you through the dungeon, Warrior Heroes Legends resolves all random encounters immediately. In addition, it adds quite a bit of fiddliness by using a deck of cards to generate and map the dungeon. The rules as written also basically expect you to constantly move forward, never going down the other corridor or checking alternative routes (which are rather rare thanks to the design anyway).
However, there is also a positive as the crawl system does add random events, which is a nice touch.
This also comes into play with another positive - if you also own 2 Hour Dungeon Crawl, you can easily integrate it into Warrior Heroes Legends with only minor adjustments needed (and maybe a decision whether to use the Big Bad and Minions tables of one or the other). In my opinion, that is a great advantage, as this combination greatly improves the experience.
There are also a lot of very nice details and gadgets - like the tables for NPC generation and interactions with them. Also the job opportunities and the encounters are well-designed and quite usable.
In the end, I have the impression that the design somewhat stopped between having only individual encounters and having a complete campaign generator. The components that are there are really good (except for the dungeon crawl), so if you are willing to fill in gaps and design the general situation, this book could be useful, although it is rather costly for what it does.