It's easier if you stop thinking of a Melee Cleric as a cleric.
It isn't.
It's a Paladin with better spells and no alignment restrictions, or a no-Rage Barb with access to heals.
Vistani Knife Fighter is a trap, IMHO. It was a gift to assassins and a lure to try to get people to use different weapon types (daggers in this case). It didn't work because assassin was still gimp and daggers are fucking terrible DPS weapons. Although to be fair, Assassin has enjoyed a renaissance of late in Reaper mode.
You best bet is to build like a Paladin (STR, CON, and WIS instead of CHA). If you had the Falconry tree, you can dump STR just low enough to qualify for Power Attack and Cleave feats and go full ham on WIS to Attack/Damage with Killer Instinct I & II. Side benfit, you have more SP and better will saves. Choose War domain since it gives the best (re: easiest to use) overall benefits for Melee:
War Domain- Level 2: You gain +1 to hit and damage with melee and ranged weapons. This increases at 4th, 8th, 12th, 16th and 20th.
- Upon Turning: When you use Turn Undead your party gains a Divine bonus to Melee Power and Ranged Power equal to half your Cleric level for 20 seconds.
- Level 5: You gain proficiency in all martial and exotic weapons.
- Level 9: Your tactical DCs are increased by half your Cleric level.
- Level 14: You gain Holy Sword as an SLA. 10 SP, 6 second cooldown.
Access to Holy Sword (+1 Crit Multi, +1 Crit Threat) THF + Cleave + Great Cleaves are your friend. Falchion in probably your best weapon choice. You won't have the feats for much else aside from maybe Quicken or Empower Healing unless you go Human or PDK.
The simplest solution is still using the Warpriest tree and taking Divine Power at Tier 5. The STR is not the lure (+6 is easily obtainable and even under powered by Lvl 12, although it may save a gear slot) the real lure is the full BAB. That opens up additional attack animations and to-hit bonuses which improve overall DPS.
You can skip it and run the spell Divine Power, but it has a short duration, can be dispelled, and you won't have the spare feats for extend. That was an option prior to Reaper when having the Radiant Aura for constant healing while in Melee was a thing. Now that's pointless.
Otherwise you'll be deep splashing into Fighter like was mentioned above and that may not be what you want.
Reaper basically made self-heals moot but you'll be much better equipped than a Paladin or Fighter, and a lot more useful in Reaper PuGs. Don't waste time gearing for better Heals, it won't help (unless you're running Elites for fast completions).
In any event, don't overthink it. A Warpriest is pure tank and spank playstyle, but you're pounding a square peg into a round hole using a Cleric. Kind of like making a good gunstock warclub

YMMV.