I think Flare deserves a second look now that Data and Destiny has been released. I mean, we only got, what, less than 2 years before it's cycled out? Now is the time for Flare to shine (see what I did there?).
By itself, Flare rezzes at a whopping 9, so you wouldn't rez it unless you were darn sure you could land the trace and trash runner cards with reckless abandon. Aside from silly combos like Amazon Industrial Zone, I don't think you're going to find a cheaper way to rez this sucker (comment to prove me wrong). Therefore, you would look to combo with cards that make Flare even more powerful to get the most of that 9 punch to your wallet.
- NBN: Making News obviously improves your traces, but Improved Tracers does even more so. One ImpTrace in NBN:MN makes Flare a STR 7 with a Trace base str of 9. Holy cow. Maybe only Sunny is not blinded by that light (see what I did again there?).
- Any deck could use Primary Transmission Dish and/or Rutherford Grid to boost the trace.
- Surveillance Sweep is interesting here, as it forces the runner to pay money to equal 6 more than your current credit pool or suffer the consequences. Even if the trace doesn't land, the runner could potentially be broke. Wouldn't that suck if there was anything else in the server behind Flare that they would need money for?
- The Cleaners increases the meat damage to 3, so I can see Flare finding a home in Weyland.
- If you really want to get some replay out of Flare, surprise the runner with a Marcus Batty.
As far as taxing goes, this will probably cost the runner around 5 or 6 to get through consistently. Either they run through it with a credit lead on you and beat the trace, or they use Faerie, Garrote, or GS Shrike M2 to break the sub. Mimic needs 2-3 SuckerEyes counters, which is a bit painful. More than likely, the runner will avoid that server or use things like Inside Job or Femme to bypass.
Overall, I think you still need to build a synergistic deck around Flare to include it. There are more synergies out now to power it up and make it more worth the rez cost. Occasionally it may be a dead draw if you're broke or against certain match-ups. It is by no means a common include, but I hope to see a couple at tournaments in the next few years.