I think the HoS material is pretty good.
1/3 races was basically a waste of page space, it added probably the worst ED in 4E (and there was some fair competition here), plus a class that is a giant trap for new players unless they have a (albeit minor) degree of system mastery and then a
very strong concept of how to play 4E tactically. At the same time I didn't really care for more options for wizards and clerics, but in saying that one has to be fair. Wizards and Clerics are nowhere near as saturated as the 4E fighter (who has 414 powers! Yikes).
So I found very little of value in this book myself. Most of the PPs and other EDs were simply underwhelming to just a "Okay, but there are better" options. Personally HoS is the most disappointing book that Wizards have released, especially because it was so important for steadying the ship post-essentials. It failed at that on every level and has only succeeded at making me less optimistic about 4E in future.
I'll grant I did like things from the book: Despite the vampire being a trap if you can play 4E well and take durable, it's a fun and interesting class. It's just the two conditions "Knows how to play 4E" and "Takes durable" that are the trick. The necromancer was pretty cool and I think making it a mage school was probably the best choice in the end. But in the end I'm sick of wizard builds (and fighters, before anyone mentions that) and I'm really not liking the racial penalties coming back. Vryloka are a pretty neat new race, but why saddle them with a crippling -2 penalty to surge value that becomes irrelevant beyond heroic anyway? It's an insult to injury feature after level 10, but level 1-4ish Vryloka's really feel it.
It's also trivially removed with a feat, just adding more weight to the ever increasing "Feat tax" arguments that get thrown around. If anyone follows the char op feedback thread, the most common complaint that nearly every poster brings up are feat taxes. I don't see why wizards continues to add these to 4E (Vampires needing durable, Vryloka needing the +2 surge feat and such forth from this book).
Being a shade creates some issues, but it should also be interesting.
The shade has absolutely no redeeming features whatsoever, it didn't even get feats to save it from being pretty much the bottom of the barrel in 4E. If you include monster manual races, it's competing with the bullywug in terms of who is actually worse.
but all of the stuff in HoS works and is perfectly usable.
I really disagree with that. I feel most of it is functional, but there is a fair amount of stuff that really doesn't sell itself on a usable manner whatsoever.
I just hope Wizards returns to form with a bang come Heroes of the Feywild. If Heroes of the Feywild is as disappointing as Heroes of Shadow, it's probable that I will lose interest in buying any new 4E products and just stick to everything from Heroes of Shadow backwards. HoS only sneaks in because I do actually kind of like some of the things in it - especially after I houserule the easy to fix errors: Vampires simply get durable for free and Vryloka have no -2 penalty to surge value. But again, Wizards has a long time before Heroes of the Feywild and if they
listen to their community I have zero doubt of HoF avoiding the problems that HoS has had (and maybe recent books in general, even going back pre-essentials!). If HoF shows that Wizards basically didn't listen to their own community and just repeats all the same silly errors again - then I think "Jumping the shark" may have happened. I did hear that Mike has a speedboat and some water skis.