I'm currently trying to plan forward for a Psi Warrior I'm playing currently. Stats are as follows: STR: 17 DEX: 14 CON: 15 INT: 12 WIS: 10 CHA: 10

As it stands, I have two choices in front of me. Either pick up a feat at level 6 (we are currently at 5) or take an ASI. I REALLY want to take the Telekinetic feat (IMHO it should've just been included in the subclass), but we currently only have 1 real damage dealer in our Rogue. So I ask you all for advice on what to do. A few notes:

-As it stands our party (per our DM's admission) has a lot of control capabilities (grapple Barb, Lore Bard, and myself)
-This campaign will most likely end between 10-14
- I see myself in combat somewhere between a Defender (I have the highest AC currently at 19) and Striker. (Yes I know those are old terms, but 4e's what I started out with)
- The options I see are to either bump my STR to 19,  take the feat and do a split to bump my STR to 18 and INT to 13 at level 8, or try to max my STR to 20 and not worry about the feats at all since we might not need it. Again, thoughts and suggestions are welcomed.

Take Telekinetic now and split the ASI at level 8 for +1 STR and +1 to something else (maybe CON or whatever stat you raised with Telekinetic).  No point denying yourself fun if you really wanted the feat.  We all play D&D to have fun and if taking the feat increases your fun then there is no reason not to take it.

Here's the big problem with Telekinetic in this build... your INT score isn't very good. Your Telekinetic shove will call for a DC13 STR save... a save that will be easily passed by most creatures you face.

You're going to want a better INT overall... it helps your whole build in multiple ways. Still, you don't have anything to use your Bonus action on regularly, so even if it fails more often than not, you're not really losing anything by throwing out telekinetic shoves round after round.'

So, with that all said... my recommendation is to go ahead and take the Telekinetic Feat at level 6 and increase your INT by 1 to a 13. Even if you fail more often than not with your telekinetic shove, it's still very dynamic battlefield control and you can use it to pull allies out of range of enemies without triggering an attack of opportunity. Plus being able to summon an invisible mage hand at-will without any visible or audible signs that you're doing it has a ton of opportunities.

Then when you hit level 8 I would do +1 to STR to round that out to an 18 and +1 to INT to top that off to a 14. I'd also focus pretty much just on boosting INT after that... you have really good stats otherwise but for a psionic having INT as your 4th lowest stat is less than ideal.

What is your fighting style? Judging by the 19 AC, you're probaly gonna be sword n board but you might be a dual wielder with plate mail. What did you do with your last ASI too? 

Though I don't have a clue what telekinetic is, but I know what it means and that will be cool for a psi warrior. I'm thinking telekinetic, but if the rogue is the only real damage dealer you might want to bump strength.

@TransmorpherDDS, I appreciate the response, the choice to go Psi Warrior was a bit last minute, hence the low INT (we started at level 1). I figured that the telekinetic feat would definitely be used as a resource-free control feature for my party until I got my INT score up. This is also the first time I've played a "full martial" so I'm not sure how vital a 20 STR would be.

I have the Defense fighting style with Chain Mail and sword and board. My last ASI was a bump to my INT score to start making the subclass viable. 

Quote from SpectrTheron >>

@TransmorpherDDS, I appreciate the response, the choice to go Psi Warrior was a bit last minute, hence the low INT (we started at level 1). I figured that the telekinetic feat would definitely be used as a resource-free control feature for my party until I got my INT score up. This is also the first time I've played a "full martial" so I'm not sure how vital a 20 STR would be.

 A 20 STR is nice to have, but not strictly necessary. I'd say that a score of 16 is pretty much all you really need to be viable, and a score of 18 is enough to excel easily all the way up to level 20. 

My thought process has increasingly been that you only need to max out your primary stat if it provides a resource essential to your class. For example, Bards only get as many uses of Inspiration as they have Charisma. Especially for something like a Swords Bard, who uses their Inspiration both as inspiration and as a resource for combat. For you, STR deals extra damage and helps to hit more often, but your proficiency bonus will grow on its own and keep you powered up without requiring max STR to get the most out of it.

Also, I think it's really cool that you went for the subclass you wanted to play despite not building the character specifically for that subclass from day 1. I think it sounds a lot more exciting both for gameplay and roleplay purposes.

Ok. I'm gonna shorten down what I think you should do with that ASI. 

1. Shield master. That will help bump your damage a little.

2. Telekinetic. It's thematic

3. Slasher. To bump strength to 18 and get some control.

4. Crusher. To bump strength, ditch the sword and take a warhammer. Your rogue will love it.

5. Peicer. Bump strength, take a Morningstar or rapier and ditch that sword to increase your DPR.

6. Increase intelligence.

This is just my opinion by the way, and in the end it's your choice.

Multiple, good points have been made in favor of taking Telekinetic, and I will second them. The tactile benefit of Telekinetic is often overlooked because, "IT DOESN'T DO 15d6 PSYCHIC PER HIT WTF?!?!?!?!?" lol. I also think it's neat, likewise said by another, that you're building towards Psi Warrior and didn't start out with the statistical intentions of it. I have often found at my tables players whom eventually take a path like that find what they're playing more enjoyable.

I took Telekinetic on my Arcane Trickster Rogue, and it has many, MANY uses in and out of combat.

Imo, taking Telekinetic will not hurt your character, and may very well open up options later on, whereas taking a bump to STR, or whatever, is pretty well linear improvement that may not necessarily add as much to how you want to play, or have your character perceived. Fighter's get the most ASI's out of all classes, so you have plenty of opportunity to bump stats accordingly. Go for Telekinetic, it's a blast (no pun intended).