Currently part of the problem I have with Broadsides and Riptides is that SMS is 40 points to put the pair on either of these guys. I think they vastly overestimate the damage it does based on old 7th ed Tau where we were basically always BS2+ with rerolls. I would like the SMS system to drop in points to help balance these units as it is currently cost inhibitive to take on every chassis.
All of our rail weapons need a rework of some kind either in increased average damage output or reduction in cost. The only Rail user so far that is worth their competitive salt is clearly Longstrike and 1 railgun shot does not an army make.
Vehicle chassis seem to be ok since they are fairly durable and have the fly keyword keeping them shooting even after getting locked in combat though the Skyray and razorshark need some love, likely in a points reduction. I expect to see some kind of vehicle upgrades in the dex and this may alleviate some of their troubles.
Not going to get into the commander vs xv8 thing because we all know it should be somewhat rebalanced in points if they ever want us to use anything other than QFC's and 3CIB ATS mander.
Slight points reduction on Aun'va, Aun'shi, Farsight and Shadowsun or increase in abilities if taken as warlord. Currently they have no place in competitive meta whereas Bobby G, Magnus and countless others are worth having around. Previously Farsight was able to deepstrike anywhere and I would like to see that return in some capacity (IE he comes in plus a unit of XV8 like they could use a homing beacon and with this his price would clearly increase).
Need some kind of synergistic kroot ability to make krootox riders more viable or points reduction.
Ghostkeel stealth drones may need to work for other stealth units (Including Shadowsun!) or needs to have higher durability since they are only ever a unit of 2 and never forces your opponent to need to shoot at a -2 to hit the keel itself thus making them glorified ablative drone wounds or be 0 points when you get the Ghostkeel or remove them altogether and make the keel -1 always and -2 when outside of 12" and remove the drones entirely.
Firesight marksman should be able to do something other than eat a force org slot for a currently terrible sniper choice. Speaking of terrible sniper choices, our sniper drones don't even snipe! Needs to either be WAY cheaper or gets a mortal wound on 6 like EVERYONE else.
Tactical drones should be sold in boxes, not just blisters of 2. (I know this isn't a codex balance but if we're putting stuff that is wrong in a list...
Tidewall gunrig needs to have some way to increase BS even if it's by 1 when it is piloted or have points reduced.
Tidewall Droneport should have it's rules for detached vs mounted switched IE if the drones come off they no longer gain the BS benefit from the user on the droneport or have points reduced.
MANY of our units are VERY good so don't take this as a list of gripes but more of a focus on what is currently lagging behind our stand out units.