Giltonio, your critical eye is appreciated. We agree in some areas for sure. I still have some other thoughts about the matter which are in contrast to your position.
Yes, the eldritch blast warlock could do all of that. And have an extra invocation and boon. However, if in melee range (it happens) they would be worse off throwing eldritch blast at disadvantage. If we do not assume being ringed by tanks, being in melee happens. That would not be good. Disadvantage leads to misses and less damage. I believe that a blade pact warlock with armor and weapons has advantages over the tome warlock as well as the chain pact in many combat situations.
If you like chain or tome (I think they are cool too!) I understand. However, I would take blade pact (myself) over the others in a situation in which I am up close and personal with the enemy, am behind enemy lines and want to take out the big bad evil guy or in some other cases. But that is just opinion. You can kill an evil guy with eldritch blast alone. I like the option of using it as well as blade.
I believe blade pact adds an option at the cost of one. With that said, I also think that with the right feats and possibility of a magic weapon, the blade pact warlock can ultimately do more damage than pure eldritch blaster, particularly if the target is not hexed. I have seen but not computed the math over the lifespan of the character. I believe this to be true up to three eldritch blasts. Four might win out especially with hex. Again, I would take the former over the later with disadvantage myself when applicable.
What we agree on is this: to get blade pact, you need to give up chain or tome feature. Blade pact cannot tank as well as a fighter. Blade pact will have 1-2 fewer invocations to "spare" at level 12. They might get some features sooner/easier if they multiclass. Agreed on all counts.
What I do not agree with some posters on is this: the blade pact will do less damage overall (heck they might blast and then slice!), that they are not survivable even if in armor and must multiclass to have potentially large impacts on the game. I think we are only talking about tanking here and I do not assume that play style myeslf.
I do not agree for hopefully fairly obvious reasons. Some say they do much less damage than others. Yes, the battlemaster is poised to do more damage in melee. Again, I do not think that is all the blade pact is supposed to be accountable for. They have (potentially) ability to disrupt and circumvent and gimp the enemy.
My plan for blade pact (single classed) warlock is simple. First, have fun and play a creepy magical warrior! Second, throw spells and blast where applicable. Draw my blade and deliver solid blows (not absolute top DPR every round!) when the enemy closes and EB would be at disadvantage. Lastly, I hope to disrupt with illusions disguises and other at will abilities where possible to hopefully have some of these aforementioned fights on favorable ground! I hope to make good use of pact boons, invocations and patron abilities of course. I might even take a great sword to the BBEG if I get up on him when others are stuck by mooks. We shall see!
What I do not plan to do is be the main "tank" if your will. If I have to plug the hole in the lines though, I am as ready as any non-fighter/barbarian and I dare say more ready than some due to armor class and damage potential.
The biggest challenge for me is the MAD as well as the feats. Given moderately and heavily armored, I get to bump my strength up by two (as of fourth level). The feat tax here is one feat to be heavily armored, in effect. The problem comes later, at level 8. I would like Great Weapon Master or polearm master. That is expensive since I would also like and ASI or perhaps warcaster.
The latter might be circumvented if I do not rely on many concentration spells in combat. I think hex can be overrated for example and might want to spend a precious slot on fireball, or charming someone, etc.
But in the end I am reminded of another fact: the game does not assume all of the feats we have access to. Playing without them is the default. As a result, if I am missing a recommended feat, I am still several feats ahead of the default assumption.
If others suggest we need all recommended feats or else risk throwing the game, I think they are forgetting feats are not required, at all. Imagine that! And the game by all accounts still works...
