You probably couldn't describe me as a raging bull when it comes to Johnson & Johnson (NYSE:JNJ) stock, but I'm a bull nonetheless. With the healthcare giant's shares at all-time highs, I still think the stock will go even higher.

However, I can fully understand why some might not be so bullish on J&J. I can even see why some investors could be bearish on the stock. Here are three key arguments in a bear case against Johnson & Johnson that this bull admits could have some validity.

Metal bear and bull figurines

Image source: Getty Images.

1. Not enough soon enough from the pipeline

In my opinion, Johnson & Johnson has one of the best pipelines around. Additional indications could be on the way for several current drugs, including Darzalex, Imbruvica, Invokana, Stelara, and Xarelto. J&J also claims promising new products, including psoriasis drug Tremfya (guselkumab) and rheumatoid arthritis drug sirukumab.

The problem, though, is that J&J's pipeline potential might not be enough soon enough to overcome some of the company's challenges. Remicade ranks at the top of that list of challenges. Pfizer (NYSE:PFE) is already marketing a biosimilar to Remicade, branded as Inflectra in the U.S. and as Remsima in Europe. Although Pfizer's first-quarter sales of $78 million for the drug was only a drop in the bucket compared to Remicade's sales of nearly $1.7 billion, it's probably just a matter of time before J&J feels the full brunt of competition.

And Remicade isn't J&J's only problem. Year-over-year sales fell in the first quarter for several other drugs, including Invokana, Procrit, Xarelto, and Zytiga. Total pharmaceuticals sales for the company in the first quarter increased an anemic 0.8% over the prior-year period.

It's great that J&J thinks it will launch or file for regulatory approval for at least 10 new drugs by 2021 that could be blockbusters. The company's current lineup, however, simply isn't delivering significant growth.

2. Consumer and medical devices segments still sluggish

You know there's a problem when Johnson & Johnson's consumer and medical devices business segments outperform its pharmaceuticals segment. But that's exactly what happened in the first quarter -- and the other two segments weren't exactly on fire.

Consumer segment sales grew all of 1% versus the first quarter of 2016. J&J's medical devices segment did a little better, with a year-over-year sales increase of 3%. I don't think those numbers caused any investors to turn cartwheels.

Johnson & Johnson bought some of the growth for these two segments. The company's 2016 acquisition of Vogue International helped improve sales for the consumer segment, while the acquisition of Abbott Medical Optics from Abbott Labs, in February, made a difference for the medical devices segment.

Sales growth is certainly better than the alternative. However, with J&J's pharmaceuticals segment struggling, investors probably shouldn't look to J&J's consumer and medical devices segments to come to the rescue.

3. Positives already baked into the share price

Johnson & Johnson's impressive stock gains in recent months have also driven its valuation higher. J&J's earnings multiple is getting close to the highest level it's been in the last 10 years.

The positives for the company (such as anticipated approval for Tremfya) could already be baked into the share price. If so, J&J's rapid rise this year could be in jeopardy.  

Bull to bear?

Are these arguments enough to flip me from a bull to a bear on Johnson & Johnson stock? Not really.

It's best to have a long-term perspective. Over the long run, J&J should perform quite well. Sure, there are stocks that have better growth prospects. There are stocks more attractively valued. There are stocks with higher dividend yields. If investors could only buy one stock, Johnson & Johnson may not be the best choice. But investors aren't restricted to just one stock.

In my view, Johnson & Johnson continues to be a solid pick for nearly any investment portfolio. I'm still a bull on this stock.

Keith Speights owns shares of Pfizer. The Motley Fool owns shares of and recommends Johnson & Johnson. The Motley Fool has a disclosure policy.