Quoth ToB, p38:
Initiating stances and manuvers:
... The process of initiating a maneuver is similar to that of casting a spell.. though there are some key differences ...
Resolving a maneuver or stance:
Many maneuvers include an attack of some kind. All offensive combat actions... all maneuvers that opponents can resist with saving throws or that otherwise harm or hamper subjects can be considered attacks.
Strike: A strike is a maneuver that allows a special attack. Strikes almost always require a standard or full-round action to complete. Many of them involve making a melee attack as part of completing the maneuver. If the attack hits, your opponent normally takes normal melee damage, as well as suffering the effect of the strike. When making a strike, you use your BAB, [and normal modifiers] as normal.
So an example of a normal strike is: "blistering flourish" from desert wind. If you hit, you glow for a minute and creatures nearby need to make a DC 11+wis or be dazzled.
death mark that explodes in a fireball is the same.
Looking at diamond mind, the action before thought counter requires a concentration check in place of a reflex save, no extra attack.
Diamond nightmare blade is the item you described. Unfortunately it looks like case one from the text and as discussed here, you roll concentration to get a 4x multiplier and make your opponent flatfooted. You then have to attack as normal.
You must make a Concentration check as part of this maneuver. The DC of this check is the target creature’s AC. You then make a single melee attack against your target, also as part of the maneuver. If your Concentration check succeeds, this attack deals four times your normal melee damage. If your check fails, your attack is made with a –2 penalty and doesn’t deal any additional damage. If your strike is a critical hit, you stack the multipliers as normal (PH 304).
Functionally this is "roll twice to do OMGWTF damage", which indicates that you should invest both in a very high concentration (or other key skill of the discipline) and a good attack bonus. Given that insightful strike replaces your damage with a concentration check... and the insane ways of boosting skill checks... this doesn't seem like an unreasonable requirement.
Every power describes its use. Most do not "replace" attacks save where they indicate that they do.