(Also I really wouldn't recommend you looking at the FW website after all they have an entire range of minis set 10,000 years before the current era which are actually some of the most awesome minis GW has ever put out but I fear they may give you an embolism, plus there is the Badab War stuff. Seriously don't go there, I fear for your health if you do.)
FW is for specialist models/games. As in, the Badab War is a specific campaign in a specific series of books, Imperial Armour. Therefore, it's perfectly fine to add characters in the game who die at some point, since each Imperial Armour book is based around a, guess what, specific campaign. Blood Angels codex isn't set around Armageddon.
Furthermore, 30k is just the same. It's set 10,000 years before and is different to 40k. You KNOW you're recreating events. I'm not pretending the Legion I'm playing is actually stomping around the world right now.
I'm perfectly fine with him being part of Armageddon, cause, guess what, that's been put in a fucking separate book as well. Oh, and look at that, Herman von Strab was put in the Armageddon HQ section in Apocalypse book, NOT IN THE IMPERIAL GUARD CODEX.
So, since your reading comprehension is lacking, I'll spell it out for you as simply as possible. If you want to specifically recreate the Armageddon camapaign, do so, there are several books available to help you do this, with specific rules and ideas and, guess what, Armageddon War specific characters. The Codexes are supposed to be about the Chapter as of 'now' not 'as of 2nd War for Armageddon'. Furthermore, it's supposed to be a list of the chapters units and their greatest heroes who are actually doing stuff, not being dead decades ago.
So, do you get it now? He's a waste of a character slot. If you want to play with him and recreate battles, fine, do it, I don't give a shit, but putting him specifically in a book when you could easily create another character (who is alive) or bring back one from the past (Moriar the Chosen for example) would be better than somebody who has no further part to play in the events of the Chapter.
You really seemed to be ignoring the fact I was describing what should happen in their 6th (but in reality, 7th) edition codex, not what already exists. People's 'fun' (what a horrible buzzword fun is, I must conform to what everybody else wants!) can be ruined simply because somebody plays Tycho instead of somebody else. Say you're playing as Chaos Chapter who have been unleashed to cause destruction in systems surrounding the Cadian Gate in an effort to divert or hold up vital supplies or manpower, this is happening around 40.999, you're playing against Blood Angels, and bam, some guy plays Tycho. You're immediately transported back in time to before he was dead (ignoring the fact if it's the Black Rage version, which he only became DURING the war itself) and thus screwing up your planned story.
Cause guess what? Some people like pretending they're trying to hold back the vanguard of the 13th Crusade, just as much as some people enjoy recreating the War for Armageddon. But playing dead characters outside specific settings cause those people to have their fun reduced.
If you can't see why he's and every other dead character is pointless in a codex, then I cannot help you. Dataslates exist for a reason, to give specific characters a presence on the table-top for those who want to fight specific scenarios.
Furthermore, if you could be so kind as to point out any other fully dead characters who are still in their main codex in 40k, I'd appreciate it. Seeing as how I'd want to avoid dying by having an opinion different to yours.