No, the argument is really about whether a normal Codex Space Marines force should field 10-man general-purpose tactical squads or smaller more dedicated - or just comparatively tougher - squads.
If you play by the fluff, you *should* field 10 man tac squads with 1 heavy and 1 special weapon, meaning each tac squad is in some ways capable of a multi-role battlefield function - this after all is the point of a tactical squad. This has the disadvantages that 1 - you have a large squad when you might want the points elsewhere and 2 - either your special or your heavy weapon isn't going to be used most of the time as you can't move and fire the heavy, but if you don't move the special is out of range - not always, but often. As Jacobite noted earlier " it's kinda pointless to put a flamer and a lascannon in the same squad" - a very valid point I feel.
The alternative ('min-max', 'powergamer' or possibly 'cheesebeard gambit') is to field more small squads - 'min-maxing' is minimum troops, maximum special/heavy weapons, so a five-man squad with one of each; you can obviously field two of these for only a few more points than a 10-man tac squad, but are doubling your specials and heavies. A very similar tactic is to effectively split the tac squad in two - five man flamer armed 'assault squad lite' and five man missile or lascannon armed 'dev squad lite'; same points as a tac squad, but one half stays still and fires every turn, the other half moves forward and fires every turn. For exactly the same points as a 10-man tac squad with its 'wasteful' spare weapon, you get two smaller dedicated tac squads each of which has a particular role.
OK you can 'only' field 6 small squads (ie 3 complete tac squads) before your force-org slots are full, on the other hand you've got 600 points to spend elsewhere and more efficient use of the points you have spent, turn-for-turn, gun-for-gun, compared to fielding 6 complete tac squads (which I've never seen anyone do, but I plan to, once I get my Battle Company sorted...).
The same principle can be applied to devastator squads - reduce the guys with bolters, maximise the number of heavies. A classic, I believe, is the '6 man las-plas combo'. But, for more fluffy players, all this is a *bad thing* as it goes against the spirit of the Codex Astartes - ie Roberte Guillame's Codex, not the GW rulebook - because everything in that is organised round the 10-man, multi-role tactical squad.
Thank you for listening to "The Tactical Squad is dead" - part one of our new serial; tune in tommorow for the second part, "Long live the Tactical Squad"...
:cyclops: