Crossbow is definitely a very suboptimal choice for a fighter to focus on. The Sword and Fist feat, Rapid Reload doesn't do much to remedy this.
Allowing one free action reload per round simply gives second level human crossbow fighters a 3shots/2 rounds ROF. (Point Blank Shot, Precise Shot, Rapid Shot, Rapid Reload; Crossbow starts loaded: Round 1: Rapid Shot, using rapid reload for the second shot, Round 2: Rapid Reload, fire (standard action), load (MEA), Round 3 Rapid Shot....) A human fighter can have a 2/1 ROF with a longbow one level earlier. (Round 1: Rapid shot, Round 2: Rapid Shot, etc). In this case (which is optimal for the crossbowman), the damage done is similar unless the bowman has a mighty composite bow in which case, he's ahead. Rapid Reload doesn't make crossbows a viable choice for fighter PCs.
What it does do is make it possible for NPCs without the archery feats to fire a heavy crossbow once per round. It's worthwhile for NPCs but lame for PCs.
So, when is a crossbow a viable weapon for a PC?
-When you're not proficient in regular bows (Wizard, cleric, monk, some rogues)
-When you've got a significant strength penalty and cannot have multiple sneak attacks per round (non archery focussed halfling rogues before level 8; any small or low strength rogues in campaigns that limit sneak attacks to 1/round).
-When you don't want to spend the money on a mighty bow (many low level fighters and paladins) but want more range than a javalin.
-When your DM creates house rules that give crossbows huge mechanical advantages. (Ignoring portions of armor would probably be enough for non-archer characters; dedicated archers wouldn't benefit though because (typically) they rarely miss anyway after the first few levels). If the DM asked, however, I'd recommend against doing this.
-When your DM creates a prestige class that makes crossbows a good weapon for fighters to choose. (I guess Deepwood Sniper could fill this role although it won't make crossbows competitive with bows for anything other than long range sniping--especially not if the class is open to bow archers).